Enhanced messaging to handle sps spoofing

ABSTRACT

Techniques are discussed herein for transmission of location information by a user equipment (UE) to other UEs. A UE receives Satellite Positioning System (SPS) signals and determines whether the SPS signals are reliable. The UE determines a location estimate to be transmitted to other UEs using the SPS signals if the SPS signals are determined to be reliable and using non-SPS information if the SPS signals are determined to be not reliable. The location information is transmitted to other UEs in a message that includes an indication of the source of information used to generate the location estimate. A UE that receives the message may determine its location estimate based, at least in part, on the indication of the source of information, e.g., by determining whether SPS signals are reliable based, at least in part, on the indication of the source of information received in the message.

BACKGROUND Background Field

The subject matter disclosed herein relates to wireless communicationssystems, and more particularly to methods and apparatuses for locationdetermination of a user equipment in a wireless communications systemand communication when location information may be unreliable.

Relevant Background

Obtaining a reliable, accurate location of one or more mobile devicesmay be useful for many applications including, for example, emergencycalls, personal navigation, asset tracking, locating a friend or familymember, etc. Existing positioning methods include methods based onmeasuring radio signals transmitted from a variety of devices orentities including satellite vehicles (SVs) and terrestrial radiosources in a wireless network such as base stations and access points.It is expected that standardization for the 5G (Fifth Generation)wireless networks will include support for various positioning methods,which may utilize reference signals transmitted by base stations in amanner similar to which LTE (Long-Term Evolution) wireless networkscurrently utilize Positioning Reference Signals (PRS) and/orCell-specific Reference Signals (CRS) for position determination.Obtaining accurate position information for user equipment, such ascellular telephones or other wireless communication devices, is becomingprevalent in the communications industry. For example, obtaining highlyaccurate locations of vehicles or pedestrians is essential forautonomous vehicle driving and pedestrian safety applications.

A common means to determine the location of a device is to use asatellite positioning system (SPS), such as the well-known GlobalPositioning Satellite (GPS) system or Global Navigation Satellite System(GNSS), which employ a number of satellites that are in orbit around theEarth. In certain scenarios, however, location determination signalsfrom an SPS may be unreliable or unavailable, e.g., during adverseweather conditions or in areas with poor satellite signal reception suchas tunnels or parking complexes. Moreover, satellite positioning systemsignals may be spoofed by overpower or replace the existing SPS signalsor other location-related signals causing mobile devices and/or otherdevices to calculate a wrong location or to obfuscate or jam orotherwise make reliable location determination difficult. It isdesirable to ensure that location information that is being communicatedbetween mobile devices, particularly for safety related applications,may be trusted.

SUMMARY

Techniques are discussed herein for transmission of location informationby a user equipment (UE) to other UEs. A UE receives SatellitePositioning System (SPS) signals and determines whether the received SPSsignals are reliable. The UE determines a location estimate to betransmitted to other UEs using the SPS signals if the received SPSsignals are determined to be reliable and using non-SPS information ifthe received SPS signals are determined to be not reliable. The locationinformation is transmitted to other UEs in a message that includes anindication of the source of information used to generate the locationestimate. A UE that receives the message may determine its locationestimate based, at least in part, on the indication of the source ofinformation, e.g., by determining whether received SPS signals arereliable based, at least in part, on the indication of the source ofinformation received in the message.

In one implementation, a method performed by a user equipment (UE) fortransmitting location information, includes receiving SPS (SatellitePositioning System) signals; determining whether the received SPSsignals are reliable; determining a location estimate to be transmittedto other UEs, wherein a source of information used to determine thelocation estimate is the SPS signals if the received SPS signals aredetermined to be reliable and the source of information used todetermine the location estimate is non-SPS information if the receivedSPS signals are determined to be not reliable; transmitting to one ormore UEs, a wireless message that includes the location estimate for theUE and an indication of the source of information used to generate thelocation estimate.

In one implementation, a user equipment (UE) configured for transmittinglocation information, includes at least one wireless transceiverconfigured to wirelessly communicate with entities in a wirelessnetwork; an SPS (Satellite Positioning System) receiver configured toreceive SPS signals; at least one memory; and at least one processorcoupled to the at least one wireless transceiver, the SPS receiver, andthe at least one memory, wherein the at least one processor isconfigured to: receive, via the SPS receiver, SPS signals; determinewhether the received SPS signals are reliable; determine a locationestimate to be transmitted to other UEs, wherein a source of informationused to determine the location estimate is the SPS signals if thereceived SPS signals are determined to be reliable and the source ofinformation used to determine the location estimate is non-SPSinformation if the received SPS signals are determined to be notreliable; transmit, via the at least one wireless transceiver, to one ormore UEs, a wireless message that includes the location estimate for theUE and an indication of the source of information used to generate thelocation estimate.

In one implementation, a user equipment (UE) configured for transmittinglocation information, the UE includes means for receiving SPS (SatellitePositioning System) signals; means for determining whether the receivedSPS signals are reliable; means for determining a location estimate tobe transmitted to other UEs, wherein a source of information used todetermine the location estimate is the SPS signals if the received SPSsignals are determined to be reliable and the source of information usedto determine the location estimate is non-SPS information if thereceived SPS signals are determined to be not reliable; and means fortransmitting to one or more UEs, a wireless message that includes thelocation estimate for the UE and an indication of the source ofinformation used to generate the location estimate.

In one implementation, a non-transitory storage medium including programcode stored thereon, the program code is operable to configure at leastone processor in a user equipment (UE) for transmitting locationinformation, the program code including instructions to: receive SPS(Satellite Positioning System) signals; determine whether the receivedSPS signals are reliable; determine a location estimate to betransmitted to other UEs, wherein a source of information used todetermine the location estimate is the SPS signals if the received SPSsignals are determined to be reliable and the source of information usedto determine the location estimate is non-SPS information if thereceived SPS signals are determined to be not reliable; and transmit toone or more UEs, a wireless message that includes the location estimatefor the UE and an indication of the source of information used togenerate the location estimate.

In one implementation, a method performed by a first user equipment (UE)for transmission of location information, includes receiving from asecond UE a wireless message that includes a location estimate for thesecond UE and an indication of a source of information used to generatethe location estimate, wherein the source of information comprises SPS(Satellite Positioning System) signals or non-SPS information; anddetermining a location estimate for the first UE at least partiallybased on the indication of the source of information used to generatethe location estimate received from the second UE.

In one implementation, a first user equipment (UE) configured fortransmitting location information, includes at least one wirelesstransceiver configured to wirelessly communicate with entities in awireless network; an SPS (Satellite Positioning System) receiverconfigured to receive SPS signals; at least one memory; and at least oneprocessor coupled to the at least one wireless transceiver, the SPSreceiver, and the at least one memory, wherein the at least oneprocessor is configured to: receive, via the at least one wirelesstransceiver, from a second UE a wireless message that includes alocation estimate for the second UE and an indication of a source ofinformation used to generate the location estimate, wherein the sourceof information comprises SPS signals or non-SPS information; anddetermine a location estimate for the first UE at least partially basedon the indication of the source of information used to generate thelocation estimate received from the second UE.

In one implementation, a first user equipment (UE) configured fortransmitting location information, the first UE includes means forreceiving from a second UE a wireless message that includes a locationestimate for the second UE and an indication of a source of informationused to generate the location estimate, wherein the source ofinformation comprises SPS (Satellite Positioning System) signals ornon-SPS information; and means for determining a location estimate forthe first UE at least partially based on the indication of the source ofinformation used to generate the location estimate received from thesecond UE.

In one implementation, a non-transitory storage medium including programcode stored thereon, the program code is operable to configure at leastone processor in a first user equipment (UE) configured for transmittinglocation information, the program code including instructions to:receive from a second UE a wireless message that includes a locationestimate for the second UE and an indication of a source of informationused to generate the location estimate, wherein the source ofinformation comprises SPS (Satellite Positioning System) signals ornon-SPS information; and determine a location estimate for the first UEat least partially based on the indication of the source of informationused to generate the location estimate received from the second UE.

BRIEF DESCRIPTION OF THE DRAWING

Non-limiting and non-exhaustive aspects are described with reference tothe following figures, wherein like reference numerals refer to likeparts throughout the various figures unless otherwise specified.

FIG. 1 is a simplified diagram of an example wireless communications andsatellite signaling environment.

FIG. 2 is a block diagram of components of an example user equipmentshown in FIG. 1.

FIG. 3 is a block diagram of components of an exampletransmission/reception point shown in FIG. 1.

FIG. 4 is a block diagram of components of an example server shown inFIG. 1.

FIG. 5 is a flow chart illustrating determination in the confidencelevel of an SPS derived location estimate and selection of locationestimate to transmit to other UEs.

FIG. 6 is a simplified diagram of an environment in which a userequipment of FIG. 2 receives anomalous and non-anomalous signals.

FIG. 7 is a signal and process flow for identifying an anomalous signal.

FIG. 8 is a signaling and process flow for determining confidence in anSPS derived position estimate and transmitting location estimate withthe source of the estimate to other UEs.

FIG. 9 illustrates a wireless communication system and transmission of alocation information message that includes a location estimate and thesource of the location information used to determine the locationestimate.

FIG. 10 illustrates a signaling and process flow showing detection ofunreliable SPS signals based on location information messages receivedfrom other UEs.

FIG. 11 illustrates a signaling and process flow showing identificationof unreliable or anomalous SPS based, at least in part, on SPS derivedlocation information from other UEs.

FIG. 12 is a flow diagram of a method of transmitting locationinformation by a UE.

FIG. 13 is a flow diagram of a method of transmitting locationinformation by a UE.

DETAILED DESCRIPTION

Inter-device communications may be used for safety application, e.g.,where cooperative or automated operation is involved. For example,inter-vehicle communications may be used for automated driving andvehicle safety applications. Inter-vehicle communications may be direct,e.g., vehicle to vehicle, or may be indirect, e.g., via aninfrastructure component such as a roadside unit (RSU), access point, orbase station. The inter-vehicle communications may include messages andinformation elements (IEs) with which a vehicle may provide informationnecessary for automated driving.

For example, for safe operation of autonomous mobile devices, such asvehicles, the relative locations of the devices need to be determinedand communicated to other mobile devices. Location information of adevice, for example, a user equipment (UE) in a vehicle, sometimesreferred to as V-UE, may be transmitted to other V-UEs and/orinfrastructure, e.g., RSU, or UEs held by a pedestrian, using directcommunication systems, such as dedicated short-range communication(DSRC), cellular Vehicle-to-Everything (C-V2X) communication, and 5G NewRadio (NR) communications.

Entities in a wireless communication system may be enabled tocontinuously transmit and receive messages that include locationinformation. By way of example, C-V2X enabled vehicles continuouslytransmit and receive Basic Safety Message (BSM) at 10 Hz rate. BSMcontains location information for the transmitting vehicle and mayfurther include other information such as speed, heading, and any otherinformation such as indications that the vehicle is braking,malfunctioning, etc. Safety features in vehicles that use such C-V2Xmessages may depend greatly on the location of the received messages.

Communication systems that depend on communications between entities inthe system for safe operation may include well-defined securitymechanisms to ensure that the communications are reliable. For example,in the C-V2X ecosystem, each transmitting vehicle signs its transmittedBSM message with a certificate. The security system of a receivingvehicle inspects the signature in a received BSM message to ensure thatthe message originated from a legitimate vehicle. Additionally, thesecurity system in the receiving vehicle may inspect the time andlocation in the BSM message to ensured that the BSM message is generatedwith a relevant time and location and is not a replayed message that hasa good certificate but was generated in another location or differenttime. Current security mechanisms are directed to prevent trust in amessage from a rogue vehicle, i.e., a vehicle that is transmittingfraudulent or illegitimate messages.

A possible source of attack in a communication system, such as a C-V2Xecosystem, is causing a vehicle to incorrectly determine its location,e.g., using spoofed satellite positioning system (SPS) signals. Theattack using spoofed SPS signals, for example, may use a set ofanomalous signals that overpower or replace the existing SPS or otherlocation-related signals to cause the mobile device to calculate a wronglocation or to obfuscate or jam or otherwise make reliable locationdetermination difficult. A vehicle, for example, may receive spoofed SPSsignals and calculate a wrong location that is transmitted by thevehicle in a BSM message signed with a legitimate certificate.

A receiving vehicle inspecting the signature in the received BSM messagewill determine it to be a good certificate. Moreover, while the time andlocation in the BSM message may be wrong, the time and location may beclose enough to expected values that the security mechanisms in thereceiving vehicle may not detect the BSM message to be a replayedmessage. Accordingly, the BSM message may be accepted and the locationinformation will be trusted and relied upon by the receiving vehicle,despite the location information, in fact, being wrong. An attack usinganomalous signals to cause a wrong location to be transmitted may beutilized to affect traffic, e.g., to clog traffic, cause trafficaccidents, or to direct autonomous vehicles to the wrong destination orto foil asset-tracking attempts. In non-vehicle devices, an attack usinganomalous signals to cause a wrong location to be transmitted betweendevices may be utilized to fool location-enabled point-of-saleprotection or other security based around transactions that are limitedto particular geographical scopes or requiring different degrees ofauthentication depending on geography.

Alternatively, if the receiving vehicle detects the incorrect locationor time in the transmitted message, the receiving vehicle may treat thetransmitting vehicle as a “rogue” vehicle and discard messages from thetransmitting vehicle. The receiving vehicle may additionally report thetransmitting vehicle as a “rogue” vehicle, resulting in the transmittingvehicle losing its certificate, which may inhibit the vehicle's abilityto operate.

Thus, it is important that the transmitting vehicle is aware of an SPSspoofing attack (or otherwise anomalous SPS signals) and does not send alocation that is determined based on spoofed or otherwise anomalous SPSsignals. For example, basic safety applications and advance applicationssuch as cooperative driving depends on the location information of thetransmitting vehicle, and transmission of incorrect location informationmay undermine these applications.

Accordingly, in an implementation, as discussed herein, a UE thatreceives SPS signals may determine whether those SPS signals arereliable, e.g., whether the SPS signals may be spoofed or otherwiseanomalous. The UE may determine a location estimate that is to betransmitted to other UEs using the SPS signals if the received SPSsignals are determined to be reliable and using non-SPS information ifthe received SPS signals are determined to be not reliable. The UEtransmits location information to other UEs in a message that includesthe location estimate and an indication of the source of informationused to generate the location estimate. A UE that receives the message,including the location estimate and the source of the location estimate,from another UE, may determine its own location, at least partially,based on the indication of the source of information. For example, theUE may use the indication of the source of information that is receivedin the message to assist in determining whether received SPS signals arereliable and may determine its own position estimate using SPS signalsif the SPS signals are determined to be reliable or using non-SPSinformation if the SPS signals are determined to be not reliable.

FIG. 1 illustrates an example wireless communications and satellitesignaling environment 100 includes a wireless communication system 110,mobile SPS-enabled devices 161, 162, 163, a satellite signal emulator170, and satellite constellations 180, 190. The wireless communicationsystem 110 includes a user equipment (UE) 112, a UE 113, a UE 114, a UE115, a UE 116, base transceiver stations (BTSs) 120, 121, 122, 123, anetwork 130, a core network 140, and an external client 150. The corenetwork 140 (e.g., a 5G core network (5GC)) may include back-end devicesincluding, among other things, an Access and Mobility ManagementFunction (AMF) 141, a Session Management Function (SMF) 142, a server143, and a Gateway Mobile Location Center (GMLC) 144. The AMF 141, theSMF 142, the server 143, and the GMLC 144 are communicatively coupled toeach other. The server 143 may be, for example, a Location ManagementFunction (LMF) that supports positioning of the UEs 112-116 (e.g., usingtechniques such as Assisted Global Navigation Satellite System (A-GNSS),OTDOA (Observed Time Difference of Arrival, e.g., Downlink (DL) OTDOAand/or Uplink (UL) OTDOA), Round Trip Time (RTT), Multi-Cell RTT, RTK(Real Time Kinematic), PPP (Precise Point Positioning), DGNSS(Differential GNSS), E-CID (Enhanced Cell ID), AoA (Angle of Arrival),AoD (Angle of Departure), etc.). The communication system 110 mayinclude additional or alternative components. The satellite signalemulator 170 may be configured to provide erroneous, e.g., spoofed, SPS(Satellite Positioning System) signals that appear to be from asatellite, which may lead to erroneous location determination, e.g., byone or more of the devices 161-163 and/or one or more of the UEs112-116. The devices 161-163 and the UEs 112-116 may be configured todetermine when an SPS derived location estimate may be untrustworthy,e.g., based on a determined confidence level generated from non-SPSinformation, and to provide transmit messages to other devices (devices161-163 and UEs 112-116) with its location information including alocation estimate (determined using SPS signals or non-SPS information),a confidence level in the location estimate, and the source ofinformation used to generate the location estimate.

An LMF may also be referred to as a Location Manager (LM), a LocationFunction (LF), a commercial LMF (CLMF), or a value-added LMF (VLMF). Theserver 143 (e.g., an LMF) and/or one or more other devices of the system110 (e.g., one or more of the UEs 112-116) may be configured todetermine locations of the UEs 112-116. The server 143 may communicatedirectly with the BTS 121 (e.g., a gNB) and/or one or more other BTSs,and may be integrated with the BTS 121 and/or one or more other BTSs.The SMF 142 may serve as an initial contact point of a Service ControlFunction (SCF) (not shown) to create, control, and delete mediasessions. The server 143 (e.g., an LMF) may be co-located or integratedwith a gNB or a TRP (Transmission/Reception Point), or may be disposedremote from the gNB and/or TRP and configured to communicate directly orindirectly with the gNB and/or the TRP.

The AMF 141 may serve as a control node that processes signaling betweenthe UEs 112-116 and the core network 140 and provides QoS (Quality ofService) flow and session management. The AMF 141 may support mobilityof the UEs 112-116 including cell change and handover and mayparticipate in supporting signaling connection to the UEs 112-116.

The system 110 is capable of wireless communication in that componentsof the system 110 can communicate with one another (at least sometimesusing wireless connections) directly or indirectly, e.g., via the BTSs120-123 and/or the network 130 (and/or one or more other devices notshown, such as one or more other base transceiver stations). Forindirect communications, the communications may be altered duringtransmission from one entity to another, e.g., to alter headerinformation of data packets, to change format, etc. The UEs 112-116shown are a smart device, such as a smartphone or smartwatch, a tabletcomputer, and a vehicle-based device, but these are examples only as theUEs 112-116 are not required to be any of these configurations, andother configurations of UEs may be used. A smart device, for example,may be any electronic device that is can be generally connected to otherdevices or networks via different wireless protocols such as Bluetooth,Zigbee, NFC, Wi-Fi, LiFi, 5G, etc., that can operate to some extentinteractively and autonomously. The UEs 112, 113 shown are mobilewireless communication devices (although they may communicate wirelesslyand via wired connections) including mobile phones (includingsmartphones) and a tablet computer. The UEs 114 and 115 shown are avehicle-based mobile wireless communication device (although the UE 114may communicate wirelessly and via wired connections). The UE 116 isshown as a generic UE and may be one or more types of UEs, whethermobile or not, whether of a type shown or not. For example, the UE 116may include one or more UEs that are, or may be associated with anentity that is, a typically-static or static device such as a roadsideunit (RSU), cash register, an automatic teller machine (ATM), arestaurant or other building, etc. Other types of UEs may includewearable devices (e.g., smart watches, smart jewelry, smart glasses orheadsets, etc.). Still other UEs may be used, whether currently existingor developed in the future. Further, other wireless devices (whethermobile or not) may be implemented within the system 110 and maycommunicate with each other and/or with the UEs 112-116, the BTSs120-123, the network 130, the core network 140, and/or the externalclient 150. For example, such other devices may include internet ofthing (IoT) devices, medical devices, home entertainment and/orautomation devices, etc. The core network 140 may communicate with theexternal client 150 (e.g., a computer system), e.g., to allow theexternal client 150 to request and/or receive location informationregarding the UEs 112-116 (e.g., via the GMLC 144).

The UEs 112-116 or other devices may be configured to communicate invarious networks and/or for various purposes and/or using varioustechnologies (e.g., 5G, Wi-Fi communication, multiple frequencies ofWi-Fi communication), satellite positioning, one or more types ofcommunications (e.g., GSM (Global System for Mobiles), CDMA (CodeDivision Multiple Access), LTE (Long-Term Evolution), V2X(Vehicle-to-everything e.g., V2P (Vehicle-to-Pedestrian), V2I(Vehicle-to-Infrastructure), V2V (Vehicle-to-Vehicle), etc.), IEEE802.11p, etc.). V2X communications may be cellular (Cellular-V2X(C-V2X)) and/or WiFi (e.g., DSRC (Dedicated Short-Range Connection)).The system 110 may support operation on multiple carriers (waveformsignals of different frequencies). Multi-carrier transmitters cantransmit modulated signals simultaneously on the multiple carriers. Eachmodulated signal may be a Code Division Multiple Access (CDMA) signal, aTime Division Multiple Access (TDMA) signal, an Orthogonal FrequencyDivision Multiple Access (OFDMA) signal, a Single-Carrier FrequencyDivision Multiple Access (SC-FDMA) signal, etc. Each modulated signalmay be sent on a different carrier and may carry pilot, overheadinformation, data, etc. The communication links shown in FIG. 1 areexamples and not limiting of the disclosure. The UEs 112-116 maycommunicate with base stations, with other UEs, etc.

The BTSs 120-123 may wirelessly communicate with the UEs 112-116 in thesystem 110 via one or more antennas. A BTS may also be referred to as abase station, an access point, a gNode B (gNB), an access node (AN), aNode B, an evolved Node B (eNB), etc. For example, each of the BTSs 120,121 may be a gNB or a transmission point gNB, the BTS 122 may be a macrocell (e.g., a high-power cellular base station) and/or a small cell(e.g., a low-power cellular base station), and the BTS 123 may be anaccess point (e.g., a short-range base station configured to communicatewith short-range technology such as WiFi, WiFi-Direct (WiFi-D),Bluetooth®, Bluetooth®-low energy (BLE), Zigbee, etc. One or more of theBTSs 120-123 may be configured to communicate with the UEs 112-116 viamultiple carriers. Each of the BTSs 120, 121 may provide communicationcoverage for a respective geographic region, e.g. a cell. Each cell maybe partitioned into multiple sectors as a function of the base stationantennas. A BTS may be any of a variety of forms such as a desktopdevice, a roadside unit (RSU), etc.

The BTSs 120-123 each comprise one or more Transmission/Reception Points(TRPs). For example, each sector within a cell of a BTS may comprise aTRP, although multiple TRPs may share one or more components (e.g.,share a processor but have separate antennas). The system 110 mayinclude only macro TRPs or the system 110 may have TRPs of differenttypes, e.g., macro, pico, and/or femto TRPs, etc. A macro TRP may covera relatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by terminals with servicesubscription. A pico TRP may cover a relatively small geographic area(e.g., a pico cell) and may allow unrestricted access by terminals withservice subscription. A femto or home TRP may cover a relatively smallgeographic area (e.g., a femto cell) and may allow restricted access byterminals having association with the femto cell (e.g., terminals forusers in a home).

The UEs 112-116 may be referred to as terminals, access terminals (ATs),mobile stations, mobile devices, subscriber units, etc. The UEs 112-116may include various devices as listed above and/or other devices. TheUEs 112-116 may be configured to connect indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links. The D2D P2P links may be supported with anyappropriate D2D radio access technology (RAT), such as LTE Direct(LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on. One or more of agroup of the UEs 112-116 utilizing D2D communications may be within ageographic coverage area of a TRP such as one or more of the BTSs120-123. Other UEs in such a group may be outside such geographiccoverage areas, or be otherwise unable to receive transmissions from abase station. Groups of the UEs 112-116 communicating via D2Dcommunications may utilize a one-to-many (1:M) system in which each UEmay transmit to other UEs in the group. A TRP of the BTSs 120-123 mayfacilitate scheduling of resources for D2D communications. In othercases, D2D communications may be carried out between UEs without theinvolvement of a TRP.

The UEs 112-116, such as V-UEs 114 and 115, may use the V2Xcommunication standard, in which information is passed between a vehicleand other entities within the wireless communication network, such RSU116. The V2X standard aims to develop autonomous or semi-autonomousdriving systems, such as Advanced Driver Assistance System (ADAS), whichhelps drivers with decisions, such as lane changes, speed changes,overtaking speeds, and may be used to assist in parking as discussedherein. The UEs 112-116 may communicate directly, e.g., peer-to-peermessaging, or via one or more intermediate entities, such as via RSU 116or BTSs 120-123 or network 130 in an infrastructure-based messaging.

In general, there are two modes of operation for V2X services, asdefined in Third Generation Partnership Project (3GPP) TS 23.285. Onemode of operation uses direct wireless communications between V2Xentities when the V2X entities, which may sometimes be referred to assidelink communication. The other mode of operation uses network basedwireless communication between entities. The two modes of operation maybe combined, or other modes of operation may be used if desired.

Entities using V2X communications, such as UEs 114 and 115 may operateusing direct or indirect wireless communications. For example, thewireless communication may be over, e.g., Proximity-based Services(ProSe) Direction Communication (PC5) reference point as defined in 3GPPTS 23.303, and may use wireless communications under IEEE 1609, WirelessAccess in Vehicular Environments (WAVE), Intelligent Transport Systems(ITS), and IEEE 802.11p, on the ITS band of 5.9 GHz, or other wirelessconnections directly between entities.

Thus, as illustrated, UEs 114 and 115 may directly communicate usingwith a Vehicle-to-Vehicle (V2V) communication link. UEs 114 and 115 maysimilarly directly communicate with a roadside unit (RSU), e.g., UE 116,via Vehicle-to-Infrastructure (V2I) communication links. The RSU 116,for example, may be a stationary infrastructure entity, that may supportV2X applications and that can exchange messages with other entitiessupporting V2X applications. An RSU may be a logical entity that maycombine V2X application logic with the functionality of base stations ina RAN, such as an eNB, ng-eNB, or eLTE (referred to as eNB-type RSU) ora gNB, or UE (referred to as UE-type RSU). The UEs 114, 115, and 116 maycommunicate with additional entities, such as additional vehicles, RSUsor with a UE 113, e.g., held by pedestrian using direct communicationlinks.

During direct communications with one or more entities in the V2Xwireless communication system 100, each entity may provide V2Xinformation, such as an identifier for the V2X entity, as well as otherinformation in messages such as Common Awareness Messages (CAM) andDecentralized Notification Messages (DENM) or Basic Safety Message(BSM), which may be used for, e.g., ADAS or safety use cases.

In other implementations, UEs 114 and 115 may indirectly communicatewith each other, e.g., through the RSU 116 via the V2I communicationlinks, respectively or through other network infrastructure such as BTSs120-123 and network 130, e.g., using cellular vehicle-to-everything(C-V2X). For example, vehicles may communicate via a base station in aRadio Access Network (RAN), such as an evolved Node B (eNB) or nextgeneration evolved Node B (ng-eNB) in LTE wireless access and/or evolvedLTE (eLTE) wireless access or a NR Node B (gNB) in Fifth Generation (5G)wireless access.

The mobile SPS-enabled devices 161-163 are configured with SPScapabilities (e.g., to determine location based on received SPSsignals). One or more of the SPS-enabled devices 161-163 may beconfigured with other capabilities, e.g., communication capabilities,similar to those of the UEs 112-116. The device 161 is an airplane andthe device 162 is an unoccupied aerial vehicle (UAV), but these areexamples only and not limiting of the disclosure. The mobile SPS-enableddevice 163 is shown as a generic SPS-enabled device. The device 163 maybe one or more mobile SPS-enabled devices such as one or more land-baseditems (e.g., a train, a truck, a tank, etc.), one or more water-baseditems (e.g., a ship, a jet-ski, etc.), and/or one or more air-baseditems (e.g., a missile, a space ship, etc.), etc. These examples arenon-limiting of the disclosure and other SPS-enabled devices may beused.

The communication system 110 may utilize information from aconstellation 180 of satellite vehicles (SVs) 181, 182, 183 and/or aconstellation 190 of SVs 191, 192, 193. Each of the constellations 180,190 may correspond to a respective Global Navigation Satellite System(GNSS) (i.e., Satellite Positioning System (SPS)) such as the GlobalPositioning System (GPS), the GLObal NAvigation Satellite System(GLONASS), Galileo, Beidou, or some other local or regional SPS such asthe Indian Regional Navigational Satellite System (IRNSS), the EuropeanGeostationary Navigation Overlay Service (EGNOS), or the Wide AreaAugmentation System (WAAS). Only three SVs are shown for each of theconstellations 180, 190, but constellations of GNSS SVs will includemore than three SVs.

Knowing the location of a UE is important for many applications and/orin many circumstances. Moreover, knowing the locations of other nearbyUEs may be important in many applications, such as in vehicle operation.UEs may transmit messages to other nearby UEs, such as CAM, and DENM,and BSM messages that may be used for ADAS or other safety use cases.These messages, for example, include the current location of thetransmitting UE, which may be derived using SPS signals. For example,current V2X standards, such as SAE (Society for Automotive Engineering)specifications J2945, J3161, J3224, J3186 etc., facilitate sharinglocation information with other UEs, and including the accuracy of thelocation information. The accuracy of the location information, forexample, is an uncertainty in a measurement location. If thetransmitting UE, however, determines an incorrect location based onanomalous SPS signals, the UE may believe the measured location has highaccuracy, e.g., low uncertainty, but the location measurement may, infact, be incorrect. If the transmitting UE transmits the incorrectlocation to other UEs, there may be significant consequences, includingtraffic incidents, and may undermine the trust and safety in the abilityof the UEs to operate. Current standards for sharing locationinformation are limited as they do not enable communication of thesource of the location information being provided. For example, if atransmitting UE determines that it is under an SPS spoofing attack orotherwise cannot rely on received SPS signals, the transmitting UE mayswitch to estimate its position based on non-SPS information, such ascached locations, sensor information, and locations of other C-V2Xvehicles. Current standards for sharing location information, however,would merely enable the transmitting UE to send the non-SPS basedlocation determination (with accuracy), but does not allow for thetransmitting UE to indicate that the source of the location informationbeing provided, e.g., that the location information is based on non-SPSbased information, or more specifically the type of non-SPS basedinformation. Moreover, the current standards do not permit communicationindicating that a transmitting UE may be under an SPS spoofing attack oris otherwise receiving anomalous and unreliable SPS signals.

An incorrect location may be determined based on erroneous inputinformation such as an incorrect SPS signal, whether the inaccuracy ofthe SPS signal is unintentional (e.g., due to SV error) or intentional(e.g., due to an entity providing one or more spoofed signals). Aspoofed signal is a signal that appears to be from a particular source(e.g., a known, trusted source) but is from a different source. Forexample, a spoofed signal may have characteristics of a signal from aGPS SV but originate from a GLONASS SV or an SPS simulator (e.g., aterrestrial-based SPS signal generator). Identifying SPS based locationestimates that are untrustworthy, e.g., due to anomalous SPS signals,and providing location information to other UEs that includes a locationestimate that is trustworthy, along with the confidence level in thelocation estimate and the source of the location estimate may help a UEmitigate the consequences of receiving such signals, and to enablecontinued safe operation of the UEs.

For example, in one implementation, a UE, such as a V-UE, may check itslocation information that is determined based on SPS with non-SPSinformation, such as cache location information and location informationderived from other (non-SPS) sensors. Checking the location informationwill enable the UE to determine a confidence level in thetrustworthiness of the location estimate. It should be understood thatthe confidence level is an indication of statistical probability thatthe estimated location is accurate, i.e., it is based on non-anomalousSPS signals, as opposed to an uncertainty in the estimated location. TheUE may additionally determine an approximate location estimate usingnon-SPS based location information, such as a reliable earlier knownlocation and information from non-SPS sensors. The UE further uselocation information received from other UEs to assist in determiningthe approximate location. In some implementations, the UE may determinethe confidence level in the SPS derived location estimate by comparingthe SPS derived location estimate to the approximate location estimatedetermined using non-SPS based location information. In otherimplementations, the UE may determine the approximate location estimateusing non-SPS based location information only if the confidence level inthe SPS based location estimate is low.

As discussed herein, if the UE determines that the SPS based locationestimate may be compromised (e.g., the confidence level is less than apredetermined threshold), the UE may transmit the non-SPS based locationestimate along with an indication of how the location estimate wasderived to other UEs. The UE may further transmit a confidence level inthe non-SPS based location estimate and may additionally provide anindication that the UE is receiving spoofed SPS signals. With all UEstransmitting the estimated locations, with an indication of how theestimated location was determined and the confidence level in theestimated location, each UE will know the “confidence level” of thelocation information of all other UEs that it is receiving.

Practically, an SPS spoofing target may be a group of vehicles in aspecific location or a single or group of targeted vehicles. A vehicleunder a SPS spoofing attack may receive “good” SPS based locations fromother vehicles that are receiving valid SPS signals, e.g., SPS signalsthat are not spoofed. A vehicle may then use the accurate locationinformation from other vehicles to help estimate its own position.Additionally, vehicles will be able to draw a moving map of the vehiclesthat are under an SPS spoofing attack or an area in which SPS signalsare not reliable. Vehicles may send this information to a trafficmanagement server to warn about the possible spoofing of specificvehicles or areas. The traffic management server may provide a warningto vehicles that SPS signals are unreliable, e.g., in specificidentified areas, which may also be used by UEs when determining aconfidence level in SPS derived location estimate.

FIG. 2 illustrates a UE 200, which may be an example of any of the UEs112-116 and comprises a computing platform including at least oneprocessor 210, memory 211 including software (SW) 280, one or moresensors 213, a transceiver interface 214 for a transceiver 215, a userinterface 216, a Satellite Positioning System (SPS) receiver 217, acamera 218. If the UE 200 is a V-UE, it may include a vehicle interface270. The processor 210, the memory 211, the sensor(s) 213, thetransceiver interface 214, the user interface 216, the SPS receiver 217,the camera 218, and the vehicle interface 270 may be communicativelycoupled to each other by a bus 220 (which may be configured, e.g., foroptical and/or electrical communication). One or more of the shownapparatus (e.g., the camera 218, vehicle interface 270 and/or one ormore of the sensor(s) 213, etc.) may be omitted from the UE 200. Theprocessor 210 may include one or more intelligent hardware devices,e.g., a central processing unit (CPU), a microcontroller, an applicationspecific integrated circuit (ASIC), etc. The processor 210 may comprisemultiple processors including a general-purpose/application processor230, which may be configured to operate as a special purpose processoras discussed herein, a Digital Signal Processor (DSP) 231, a modemprocessor 232, a video processor 233, a sensor processor 234 and/or aposition processor 235 (which may sometimes be referred to as a positionengine 235). One or more of the processors 230-235 may comprise multipledevices (e.g., multiple processors). For example, the sensor processor234 may comprise, e.g., processors for radar, sonar, ultrasound, and/orlidar, etc. The modem processor 232 may support dual SIM/dualconnectivity (or even more SIMs). For example, a SIM (SubscriberIdentity Module or Subscriber Identification Module) may be used by anOriginal Equipment Manufacturer (OEM), and another SIM may be used by anend user of the UE 200 for connectivity. The memory 211 is anon-transitory storage medium that may include random access memory(RAM), flash memory, disc memory, and/or read-only memory (ROM), etc.The memory 211 stores the software 280 which may be processor-readable,processor-executable software code containing instructions that areconfigured to, when executed, cause the processor 210 to operate as aspecial purpose computer programmed to perform the various functionsdescribed herein. Alternatively, the software 280 may not be directlyexecutable by the processor 210 but may be configured to cause theprocessor 210, e.g., when compiled and executed, to perform thefunctions. The description may refer only to the processor 210performing a function, but this includes other implementations such aswhere the processor 210 executes software and/or firmware. Thedescription may refer to the processor 210 performing a function asshorthand for one or more of the processors 230-235 performing thefunction. The description may refer to the UE 200 performing a functionas shorthand for one or more appropriate components of the UE 200performing the function. The processor 210 may include a memory withstored instructions in addition to and/or instead of the memory 211.Functionality of the processor 210 is discussed more fully below.

The configuration of the UE 200 shown in FIG. 2 is an example and notlimiting of the aspects of the disclosure, including the claims, andother configurations may be used. For example, an example configurationof the UE includes one or more of the processors 230-235 of theprocessor 210, the memory 211, and the wireless transceiver 240. Otherexample configurations include one or more of the processors 230-235 ofthe processor 210, the memory 211, the wireless transceiver 240, and oneor more of the sensor(s) 213, the user interface 216, the SPS receiver217, the camera 218, and/or the wired transceiver 250.

The UE 200 may comprise the modem processor 232 that may be capable ofperforming baseband processing of signals received and down-converted bythe transceiver 215 and/or the SPS receiver 217. The modem processor 232may perform baseband processing of signals to be upconverted fortransmission by the transceiver 215. Also or alternatively, basebandprocessing may be performed by the processor 230 and/or the DSP 231.Other configurations, however, may be used to perform basebandprocessing.

The UE 200 may include the sensor(s) 213 that may include, for example,one or more of various types of sensors such as one or more inertialsensors, one or more magnetometers, one or more environment sensors, oneor more optical sensors, one or more weight sensors, and/or one or moreradio frequency (RF) sensors, etc. An inertial measurement unit (IMU)may comprise, for example, one or more accelerometers (e.g.,collectively responding to acceleration of the UE 200 in threedimensions) and/or one or more gyroscopes. The sensor(s) 213 may includeone or more magnetometers to determine orientation (e.g., relative tomagnetic north and/or true north) that may be used for any of a varietyof purposes, e.g., to support one or more compass applications. Theenvironment sensor(s) may comprise, for example, one or more temperaturesensors, one or more barometric pressure sensors, one or more ambientlight sensors, one or more camera imagers, and/or one or moremicrophones, etc. The sensor(s) 213 may include RADAR (Radio Detectionand Ranging) sensors, LIDAR (Light Detection and Ranging) sensors, SONAR(Sound Navigation and Ranging), ultrasound ranging, etc., fordetermining ranges to objects. The sensor(s) 213 may further include alocal oscillator for tracking time. The sensor(s) 213 may include one ormore vision systems (e.g., including the camera 218), and/or one or moredevice sensor such as one or more vehicle sensors (e.g., an odometer, aspeedometer, a tachometer, a wheel revolution counter, etc.), and/or oneor more other sensors. The sensor(s) 213 may generate analog and/ordigital signals indications of which may be stored in the memory 211 andprocessed by the DSP 231 and/or the processor 230 in support of one ormore applications such as, for example, applications directed topositioning and/or navigation operations.

The sensor(s) 213 may be used in relative location measurements,relative location determination, motion determination, etc. Informationdetected by the sensor(s) 213 may be used for motion detection, relativedisplacement, dead reckoning, sensor-based location determination,and/or sensor-assisted location determination. The sensor(s) 213 may beuseful to determine whether the UE 200 is fixed (stationary) or mobileand/or whether to report certain useful information to the server 143regarding the mobility of the UE 200. For example, based on theinformation obtained/measured by the sensor(s), the UE 200 maynotify/report to the server 143 that the UE 200 has detected movementsor that the UE 200 has moved, and report the relativedisplacement/distance (e.g., via dead reckoning, or sensor-basedlocation determination, or sensor-assisted location determinationenabled by the sensor(s) 213). In another example, for relativepositioning information, the sensors/IMU can be used to determine theangle and/or orientation of the other device with respect to the UE 200,etc.

The IMU may be configured to provide measurements about a direction ofmotion and/or a speed of motion of the UE 200, which may be used inrelative location determination. For example, one or more accelerometersand/or one or more gyroscopes of the IMU may detect, respectively, alinear acceleration and a speed of rotation of the UE 200. The linearacceleration and speed of rotation measurements of the UE 200 may beintegrated over time to determine an instantaneous direction of motionas well as a displacement of the UE 200. The instantaneous direction ofmotion and the displacement may be integrated to track a location of theUE 200. For example, a reference location of the UE 200 may bedetermined, e.g., using the SPS receiver 217 (and/or by some othermeans) for a moment in time and measurements from the accelerometer(s)and gyroscope(s) taken after this moment in time may be used in deadreckoning to determine present location of the UE 200 based on movement(direction and distance) of the UE 200 relative to the referencelocation.

The magnetometer(s) may determine magnetic field strengths in differentdirections which may be used to determine orientation of the UE 200. Forexample, the orientation may be used to provide a digital compass forthe UE 200. The magnetometer may be a two-dimensional magnetometerconfigured to detect and provide indications of magnetic field strengthin two orthogonal dimensions. Alternatively, the magnetometer may be athree-dimensional magnetometer configured to detect and provideindications of magnetic field strength in three orthogonal dimensions.The magnetometer may provide means for sensing a magnetic field andproviding indications of the magnetic field, e.g., to the processor 210.

The transceiver 215 may include a wireless transceiver 240 and a wiredtransceiver 250 configured to communicate with other devices throughwireless connections and wired connections, respectively. For example,the wireless transceiver 240 may include a transmitter 242 and receiver244 coupled to one or more antennas 246 for transmitting (e.g., on oneor more uplink channels) and/or receiving (e.g., on one or more downlinkchannels) wireless signals 248 and transducing signals from the wirelesssignals 248 to wired (e.g., electrical and/or optical) signals and fromwired (e.g., electrical and/or optical) signals to the wireless signals248. Thus, the transmitter 242 may include multiple transmitters thatmay be discrete components or combined/integrated components, and/or thereceiver 244 may include multiple receivers that may be discretecomponents or combined/integrated components. The wireless transceiver240 may be configured to communicate signals (e.g., with TRPs and/or oneor more other devices such as other UEs) according to a variety of radioaccess technologies (RATs) such as 5G New Radio (NR), GSM (Global Systemfor Mobiles), UMTS (Universal Mobile Telecommunications System), AMPS(Advanced Mobile Phone System), CDMA (Code Division Multiple Access),WCDMA (Wideband CDMA), LTE (Long-Term Evolution), LTE Direct (LTE-D),3GPP LTE-V2X (PC5), IEEE 802.11 (including IEEE 802.11p), WiFi, WiFiDirect (WiFi-D), Bluetooth®, Zigbee, etc. The wireless transceiver 240may be configured to communicate signals in one or more of various typesof networks including WWAN (Wireless Wide Area Network), WLAN (WirelessLocal Area Network), etc. New Radio may use mm-wave frequencies and/orsub-6 GHz frequencies. The wired transceiver 250 may include atransmitter 252 and a receiver 254 configured for wired communication,e.g., with the network 130 to send communications to, and receivecommunications from, the UE 200, for example. The transmitter 252 mayinclude multiple transmitters that may be discrete components orcombined/integrated components, and/or the receiver 254 may includemultiple receivers that may be discrete components orcombined/integrated components. The wired transceiver 250 may beconfigured, e.g., for optical communication and/or electricalcommunication. The transceiver 215 may be communicatively coupled to thetransceiver interface 214, e.g., by optical and/or electricalconnection. The transceiver interface 214 may be at least partiallyintegrated with the transceiver 215.

The user interface 216 may comprise one or more of several devices suchas, for example, a speaker, microphone, display device, vibrationdevice, keyboard, touch screen, etc. The user interface 216 may includemore than one of any of these devices. The user interface 216 may beconfigured to enable a user to interact with one or more applicationshosted by the UE 200. For example, the user interface 216 may storeindications of analog and/or digital signals in the memory 211 to beprocessed by DSP 231 and/or the general-purpose processor 230 inresponse to action from a user. Similarly, applications hosted on the UE200 may store indications of analog and/or digital signals in the memory211 to present an output signal to a user. The user interface 216 mayinclude an audio input/output (I/O) device comprising, for example, aspeaker, a microphone, digital-to-analog circuitry, analog-to-digitalcircuitry, an amplifier and/or gain control circuitry (including morethan one of any of these devices). Other configurations of an audio I/Odevice may be used. Also or alternatively, the user interface 216 maycomprise one or more touch sensors responsive to touching and/orpressure, e.g., on a keyboard and/or touch screen of the user interface216.

The SPS receiver 217 (e.g., a Global Positioning System (GPS) receiver)may be capable of receiving and acquiring SPS signals 260 via an SPSantenna 262. The antenna 262 is configured to transduce the wirelesssignals 260 to wired signals, e.g., electrical or optical signals, andmay be integrated with the antenna 246. The SPS receiver 217 may beconfigured to process, in whole or in part, the acquired SPS signals 260for estimating a location of the UE 200. For example, the SPS receiver217 may be configured to determine location of the UE 200 bymulti-lateration using the SPS signals 260. The SPS signals 260 may befrom one or more SPS constellations, e.g., the constellations 180, 190and the SPS receiver 217 may be configured as a multi-SPS (multi-GNSS)to process SPS signals from multiple SPSs. The SPS signals 260 mayinclude signals of a variety of SPS frequency bands and the SPS receiver217 may be configured as a multi-band SPS receiver to receive andprocess SPS signals of multiple bands. The at least one processor 230,the memory 211, the DSP 231 and/or one or more additional specializedprocessors (not shown) may be utilized to process acquired SPS signals,in whole or in part, and/or to calculate an estimated location of the UE200, in conjunction with the SPS receiver 217. Any processor of the SPSreceiver 217 for processing of signals received by the SPS receiver 217may be considered to be part of the processor 210, and thus thedescription herein may refer to a processor of a UE (e.g., the processor210 of the UE 200) as processing one or more SPS signals (e.g.,determining one or more measurements of one or more SPS signals). Thememory 211 may store indications (e.g., measurements) of the SPS signals260 and/or other signals (e.g., signals acquired from the wirelesstransceiver 240) for use in performing positioning operations. Thegeneral-purpose processor 230 configured to operate as a special purposecomputer, the DSP 231, and/or one or more specialized processors, and/orthe memory 211 may provide or support a location engine for use inprocessing measurements to estimate a location of the UE 200.

The UE 200 may include the camera 218 for capturing still or movingimagery. The camera 218 may comprise, for example, an imaging sensor(e.g., a charge coupled device or a CMOS imager), a lens,analog-to-digital circuitry, frame buffers, etc. Additional processing,conditioning, encoding, and/or compression of signals representingcaptured images may be performed by the general-purpose processor 230and/or the DSP 231. Also or alternatively, the video processor 233 mayperform conditioning, encoding, compression, and/or manipulation ofsignals representing captured images. The video processor 233 maydecode/decompress stored image data for presentation on a display device(not shown), e.g., of the user interface 216.

The position engine 235 may be configured to determine a position of theUE 200, motion of the UE 200, and/or relative position of the UE 200,and/or time. For example, the position engine 235 may communicate with,and/or include some or all of, the SPS receiver 217. The position engine235 may work in conjunction with one or more other processors in theprocessor 210 and the memory 211 as appropriate to perform at least aportion of one or more positioning methods, although the descriptionherein may refer only to the position engine 235 being configured toperform, or performing, in accordance with the positioning method(s).Moreover, the position engine 235 may be part of or integrated with anyprocessor in processor 210, such as application processor 230. Theposition engine 235 may also or alternatively be configured to determinelocation of the UE 200 using non-SPS information such asterrestrial-based signals (e.g., at least some of the signals 248, suchas received cellular signals or LAN signals, such as WiFi, or othershort wave signals, such as ultrawideband (UWB), mmWave, etc.) formulti-lateration, for assistance with obtaining and using the SPSsignals 260, or both. The position engine 235 may be configured to useone or more other techniques (e.g., relying on the UE's self-reportedlocation (e.g., part of the UE's position beacon)) for determining thelocation of the UE 200, and may use a combination of techniques (e.g.,SPS and terrestrial positioning signals) to determine the location ofthe UE 200. The position engine 235 may be further configured todetermine the position of the UE 200 using non-SPS information, such asprevious (cached) location information, sensor information obtained fromone or more of the sensors 213 (e.g., gyroscope(s), accelerometer(s),magnetometer(s), etc.) that may sense orientation and/or motion of theUE 200 and provide indications thereof that the processor 210 (e.g., theposition engine 235 or the processor 230 and/or the DSP 231) may beconfigured to use to determine motion (e.g., a velocity vector and/or anacceleration vector) of the UE 200. The position engine 235 may furtheruse location information received from one or more UEs, such as theestimated location of the other UEs, as well as determined ranges to theUEs to determine a position of the UE. The position engine 235 may beconfigured to provide indications of uncertainty and/or error in thedetermined position and/or motion.

The vehicle interface 270 may be used by the UE 200 to provide aninterface with and control over the automated driving of a vehicle inwhich the UE 200 may be located. The vehicle interface 270, for example,may provide commands for the automated driving of the vehicle, such ascontrol over acceleration, deceleration, speed, trajectory, etc.

The memory 211 may store software 280 that contains executable programcode or software instructions that when executed by the processor 210may cause the processor 210 to operate as a special purpose computerprogrammed to perform the functions disclosed herein. The descriptionherein may refer to the UE 200 performing a function as shorthand forone or more appropriate components (e.g., the processor 210 configuredby executable program code stored in the memory 211) of the UE 200performing the function. As illustrated, the memory 211 may include oneor more components or modules that may be implemented by the processor210 to perform the disclosed functions. While the components or modulesare illustrated as software 280 in memory 211 that is executable by theprocessor 210, it should be understood that the components or modulesmay be stored in another computer readable medium or may be dedicatedhardware either in the processor 210 or off the processor. A number ofsoftware modules and data tables may reside in the memory 211 and beutilized by the processor 210 in order to manage both communications andthe functionality described herein. It should be appreciated that theorganization of the contents of the memory 211 as shown is merelyexemplary, and as such the functionality of the modules and/or datastructures may be combined, separated, and/or be structured in differentways depending upon the implementation.

The memory 211, for example, may include a location determination module282 that when implemented by the one or more processors 210 configuresthe one or more processors 210, e.g., processor 230 or position engine235, to determine a location of the UE 200 in one or more ways. The oneor more processors 210, for example, may be configured to determine alocation estimate of the UE 200 based on SPS signals received by the SPSreceiver 217, which may include anomalous signals that will produce anincorrect location estimate. The one or more processors 210 may befurther configured to determine an estimated location of the UE 200based on non-SPS information, such as previous estimated locations(i.e., cached location information stored in memory 211), sensorinformation obtained from sensors 213, and location information receivedfrom other nearby UEs, e.g., via transceiver 240, or a combinationthereof. The one or more processors 210, for example, may be configuredto determine a location estimate using cellular signals and/or wirelesslocal area network signals, e.g., from base transceiver stations (BTSs)120, 121, 122, 123 or from other UEs in sidelink signaling, e.g., usingtime difference of arrival (TDOA), angle of arrival (AoA), receivedsignal strength (RSS), or other known measurements. The one or moreprocessors 210, for example, may be configured to determine atime-filtered location of the UE 200 by using a filter, e.g., a Kalmanfilter, to calculate location using measurements over time. The one ormore processors 210 may be configured, for example, for dead reckoningfrom a previous estimated location using sensor information receivedfrom sensors 213. The one or more processors 210 may be configured touse sidelink positioning, e.g., using locations received from a numberof different entities, e.g., UEs, along with ranging to the entities(e.g., from radar, lidar, sonar or wireless ranging techniques, such asround trip time measurements) to determine an estimated location, e.g.,using multilateration techniques. The one or more processors 210 may beconfigured to use multiple different techniques and sources of data todetermine a location estimate, e.g., using different weights based onconfidence levels for various sources of data or techniques. Forexample, the one or more processors 210 may be configured to may adjusta weighting of (e.g., apply a weighting factor between 0 and 1) tovarious sources of data or may adjust the weight positioning techniques(e.g., dead reckoning vs RTT/multilateration) used in determining thelocation of the UE 200 based on confidence levels in the source of data.The one or more processors 210 may be further configured to determine aconfidence level in the non-SPS derived location estimate, e.g., basedon the types of data used to determine the location estimate, as well asconfidence levels associated with the data used.

The memory 211, for example, may include an anomaly detection module 284that when implemented by the one or more processors 210 configures theone or more processors 210 to determine whether SPS signals received arereliable or anomalous, e.g., spoofed, and producing unreliable locationestimate. The one or more processors 210, for example, may be configuredto determine a confidence level in an SPS derived location estimate. Theconfidence level, for example, may be determined by comparing the timederived from the SPS signals to a local time, e.g., determined from alocal oscillator in sensors 213 or from wireless signals received fromBTSs via transceiver 240, e.g., where closely matching times provides agreater confidence level than mis-matched times. The one or moreprocessors 210 may be additionally or alternatively configured todetermine a confidence level based on the SPS derived location estimateand non-SPS information, such as previous estimated locations (i.e.,cached location information stored in memory 211), sensor informationobtained from sensors 213, and location information received from othernearby UEs, e.g., via transceiver 240, or a combination thereof. Forexample, the one or more processors 210 may be configured to determinethe degree to which the SPS derived location estimate is aligned withcached location estimates and/or locations received from nearby UEs. Theone or more processors 210 may be configured to determine whetherchanges in the location of the UE 200 as indicated by the SPS derivedlocation estimate with respect to a previous location estimatecorresponds to data obtained from sensors 213, e.g. acceleration,velocity, orientation. The one or more processors 210 may be configuredto determine a difference between the SPS derived location estimate anda non-SPS derived location estimate, e.g., generated using non-SPSinformation, where closely matching locations provides a greaterconfidence level than mis-matched locations. In generating theconfidence level, the one or more processors 210 may be configured toprovide different weights for different kinds of disparities, e.g.,noisy sensors may be given less weight than sensors with little noise.Additionally, the one or more processors 210 may be configured tocompare the confidence level to a predetermined threshold, e.g., todetermine if the SPS based location estimate is reliable (if theconfidence level is greater than the threshold) or unreliable (if theconfidence level is less than the threshold). The one or more processors210 may be configured to determine the reliability of the SPS signalsand, accordingly, a position estimate based on the SPS signals ornon-SPS information, at least partially based on information receivedfrom other UEs or a traffic location server, such as whether the sourceof location information for other UEs is non-SPS information, theconfidence levels of the estimated locations from other UEs or a warningthat anomalous SPS signals have been detected by nearby UEs. The one ormore processors 210, for example, may be configured to determine whetherSPS signals are reliable based on location information messages receivedfrom one or more V-UEs. For example, the one or more processors 210 maybe configured to determine if SPS signals are reliable based on a numberof V-UEs using non-SPS information for location estimates, associating alow confidence level with SPS based location estimates, providing anindication that SPS signals received by the V-UE were determined to beanomalous, etc. In an implementation, where the UE 200 is an RSU, theone or more processors 210 may be configured to determine if SPS signalsare reliable for the V-UEs, e.g., based on location estimates providedby the V-UEs, and in some implementations, based on additionalinformation, such as determined ranges between V-UEs.

The memory 211, for example, may include a location information reportmodule 286 that when implemented by the one or more processors 210configures the one or more processors 210 to produce and transmit amessage that includes location information for the UE 200 or to receivelocation information for other UEs, via transceiver 240. The locationinformation includes a determined location estimate and the source ofthe location estimate. For example, the location estimate may be an SPSderived location estimate if there is high confidence in the SPS derivedlocation estimate, i.e., the received SPS signals are not determined tobe anomalous, or may be a non-SPS derived location estimate if there islow confidence in the SPS derived location estimate. The source of thelocation estimate may be an identification of the source of data, e.g.,SPS signals or non-SPS data. In some implementations, the source of datamay be further refined to the SPS constellation, carrier frequency,etc., or the type of sensor data or techniques used to generate thenon-SPS based location estimate, such as SPS signals, cellular signals,LAN signals, sidelink signals, TDOA measurements, AoA measurements, andRSS measurements, etc. The transmitted location information that istransmitted or received may further include the determined confidencelevel associated with the location estimate in the location informationmessage. The one or more processors 210 may additionally be configuredto receive similar location information from one or more other UEs, viathe transceiver 240. The messages may be V2X type messages or otherdirect or indirect messages to other nearby UEs. The messages may be,e.g., CAM, DENM, or BSM messages, e.g., used for safety applications,such as ADAS. In some implementations, other types of messaging betweenUEs may be used, e.g., if the UE 200 is a non-vehicle related UE. Theone or more processors 210 may additionally be configured to transmit,via the transceiver 240, to a traffic location server or other UEs anindication when received SPS signals have been determined to beanomalous, e.g., along with location information, such as a determinedlocation estimate and optionally, the source of the location estimateand/or confidence level. The one or more processors 210 may additionallybe configured to receive, via the transceiver 240, a warning from atraffic location server or other UEs with an indication when SPS signalsin the area of the UE 200 have been determined to be anomalous by otherUEs.

The methodologies described herein may be implemented by various meansdepending upon the application. For example, these methodologies may beimplemented in hardware, firmware, software, or any combination thereof.For a hardware implementation, the one or more processors 210 may beimplemented within one or more application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors, controllers, micro-controllers,microprocessors, electronic devices, other electronic units designed toperform the functions described herein, or a combination thereof.

For a firmware and/or software implementation, the methodologies may beimplemented with modules (e.g., procedures, functions, and so on) thatperform the functions described herein. Any machine readable mediumtangibly embodying instructions may be used in implementing themethodologies described herein. For example, software codes may bestored in a non-transitory computer readable medium such as memory 211that is connected to and executed by the one or more processors 210.Memory may be implemented within the one or more processors or externalto the one or more processors. As used herein the term “memory” refersto any type of long term, short term, volatile, nonvolatile, or othermemory and is not to be limited to any particular type of memory ornumber of memories, or type of media upon which memory is stored.

If implemented in firmware and/or software, the functions may be storedas one or more instructions or program code on a non-transitory computerreadable medium, such memory 211. Examples include computer readablemedia encoded with a data structure and computer readable media encodedwith a computer program. For example, the non-transitory computerreadable medium including program code stored thereon may includeprogram code to determination of anomalous SPS signals and transmissionof location information along with the source of the locationinformation, in a manner consistent with disclosed embodiments.Non-transitory computer readable medium includes physical computerstorage media. A storage medium may be any available medium that can beaccessed by a computer. By way of example, and not limitation, suchnon-transitory computer readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to storedesired program code in the form of instructions or data structures andthat can be accessed by a computer; disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer readable media.

In addition to storage on computer readable medium such as memory 211,instructions and/or data may be provided as signals on transmissionmedia included in a communication apparatus. For example, acommunication apparatus may include a transceiver 240 or 250 havingsignals indicative of instructions and data. The instructions and dataare configured to cause one or more processors to implement thefunctions outlined in the claims. That is, the communication apparatusincludes transmission media with signals indicative of information toperform disclosed functions.

Memory 211 may represent any data storage mechanism. Memory 211 mayinclude, for example, a primary memory and/or a secondary memory.Primary memory may include, for example, a random access memory, readonly memory, etc. While illustrated in this example as being separatefrom one or more processors 210, it should be understood that all orpart of a primary memory may be provided within or otherwiseco-located/coupled with the one or more processors 210. Secondary memorymay include, for example, the same or similar type of memory as primarymemory and/or one or more data storage devices or systems, such as, forexample, a disk drive, an optical disc drive, a tape drive, a solidstate memory drive, etc.

In certain implementations, secondary memory may be operativelyreceptive of, or otherwise configurable to couple to a non-transitorycomputer readable medium. As such, in certain example implementations,the methods and/or apparatuses presented herein may take the form inwhole or part of a computer readable medium that may include computerimplementable code stored thereon, which if executed by one or moreprocessors 210 may be operatively enabled to perform all or portions ofthe example operations as described herein. Computer readable medium maybe a part of memory 211.

FIG. 3 illustrates an example of a TRP 300 of the BTSs 120-123 thatcomprises a computing platform including at least one processor 310,memory 311 including software (SW) 312, and a transceiver 315. Theprocessor 310, the memory 311, and the transceiver 315 may becommunicatively coupled to each other by a bus 320 (which may beconfigured, e.g., for optical and/or electrical communication). One ormore of the shown apparatus (e.g., a wireless interface) may be omittedfrom the TRP 300. The processor 310 may include one or more intelligenthardware devices, e.g., a central processing unit (CPU), amicrocontroller, an application specific integrated circuit (ASIC), etc.The processor 310 may comprise multiple processors (e.g., including oneor more of an application processor, a DSP, a modem processor, a videoprocessor, and/or a sensor processor as shown in FIG. 2). The memory 311is a non-transitory storage medium that may include random access memory(RAM)), flash memory, disc memory, and/or read-only memory (ROM), etc.The memory 311 stores the software 312 which may be processor-readable,processor-executable software code containing instructions that areconfigured to, when executed, cause the processor 310 to operate as aspecial purpose computer programmed to perform various functionsdescribed herein. Alternatively, the software 312 may not be directlyexecutable by the processor 310 but may be configured to cause theprocessor 310, e.g., when compiled and executed, to operate as a specialpurpose computer programmed to perform the functions. The descriptionmay refer only to the processor 310 performing a function, but thisincludes other implementations such as where the processor 310 executessoftware and/or firmware. The description may refer to the processor 310performing a function as shorthand for one or more of the processorscontained in the processor 310 performing the function. The descriptionmay refer to the TRP 300 performing a function as shorthand for one ormore appropriate components of the TRP 300 (and thus of one of the BTSs120-123) performing the function. The processor 310 may include a memorywith stored instructions in addition to and/or instead of the memory311. Functionality of the processor 310 is discussed more fully below.

The transceiver 315 may include a wireless transceiver 340 and a wiredtransceiver 350 configured to communicate with other devices throughwireless connections and wired connections, respectively. For example,the wireless transceiver 340 may include a transmitter 342 and receiver344 coupled to one or more antennas 346 for transmitting (e.g., on oneor more uplink channels) and/or receiving (e.g., on one or more downlinkchannels) wireless signals 348 and transducing signals from the wirelesssignals 348 to wired (e.g., electrical and/or optical) signals and fromwired (e.g., electrical and/or optical) signals to the wireless signals348. Thus, the transmitter 342 may include multiple transmitters thatmay be discrete components or combined/integrated components, and/or thereceiver 344 may include multiple receivers that may be discretecomponents or combined/integrated components. The wireless transceiver340 may be configured to communicate signals (e.g., with the UE 200, oneor more other UEs, and/or one or more other devices) according to avariety of radio access technologies (RATs) such as 5G New Radio (NR),GSM (Global System for Mobiles), UMTS (Universal MobileTelecommunications System), AMPS (Advanced Mobile Phone System), CDMA(Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-TermEvolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11(including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbeeetc. The wired transceiver 350 may include a transmitter 352 and areceiver 354 configured for wired communication, e.g., with the network130 to send communications to, and receive communications from, theserver 143, for example. The transmitter 352 may include multipletransmitters that may be discrete components or combined/integratedcomponents, and/or the receiver 354 may include multiple receivers thatmay be discrete components or combined/integrated components. The wiredtransceiver 350 may be configured, e.g., for optical communicationand/or electrical communication.

The configuration of the TRP 300 shown in FIG. 3 is an example and notlimiting of the aspects of the disclosure, including the claims, andother configurations may be used. For example, the description hereindiscusses that the TRP 300 is configured to perform or performs severalfunctions, but one or more of these functions may be performed by theserver 143 and/or the UE 200 (i.e., the server 143 and/or the UE 200 maybe configured to perform one or more of these functions).

FIG. 4 illustrates a server 400, which is an example of the server 143,that comprises a computing platform including at least one processor410, memory 411 including software (SW) 412, and a transceiver 415. Theserver 400, for example, may be a traffic control server, configured toreceive indications from UEs when SPS signals are determined to beanomalous, and to provide warnings to UEs in areas where anomalous SPSsignals have been detected. The processor 410, the memory 411, and thetransceiver 415 may be communicatively coupled to each other by a bus420 (which may be configured, e.g., for optical and/or electricalcommunication). One or more of the shown apparatus (e.g., a wirelessinterface) may be omitted from the server 400. The processor 410 mayinclude one or more intelligent hardware devices, e.g., a centralprocessing unit (CPU), a microcontroller, an application specificintegrated circuit (ASIC), etc. The processor 410 may comprise multipleprocessors (e.g., including at least one of an application processor, aDSP, a modem processor, a video processor, and/or a sensor processorsimilar to that shown in FIG. 2). The memory 411 is a non-transitorystorage medium that may include random access memory (RAM)), flashmemory, disc memory, and/or read-only memory (ROM), etc. The memory 411stores the software 412 which may be processor-readable,processor-executable software code containing instructions that areconfigured to, when executed, cause the processor 410 to operate as aspecial purpose computer programmed to perform various functionsdescribed herein. Alternatively, the software 412 may not be directlyexecutable by the processor 410 but may be configured to cause theprocessor 410, e.g., when compiled and executed, to operate as a specialpurpose computer programmed to perform the functions. The descriptionmay refer only to the processor 410 performing a function, but thisincludes other implementations such as where the processor 410 executessoftware and/or firmware. The description may refer to the processor 410performing a function as shorthand for one or more of the processorscontained in the processor 410 performing the function. The descriptionmay refer to the server 400 performing a function as shorthand for oneor more appropriate components of the server 400 performing thefunction. The processor 410 may include a memory with storedinstructions in addition to and/or instead of the memory 411.Functionality of the processor 410 is discussed more fully below.

The transceiver 415 may include a wireless transceiver 440 and a wiredtransceiver 450 configured to communicate with other devices throughwireless connections and wired connections, respectively. For example,the wireless transceiver 440 may include a transmitter 442 and receiver444 coupled to one or more antennas 446 for transmitting (e.g., on oneor more uplink channels) and/or receiving (e.g., on one or more downlinkchannels) wireless signals 448 and transducing signals from the wirelesssignals 448 to wired (e.g., electrical and/or optical) signals and fromwired (e.g., electrical and/or optical) signals to the wireless signals448. Thus, the transmitter 442 may include multiple transmitters thatmay be discrete components or combined/integrated components, and/or thereceiver 444 may include multiple receivers that may be discretecomponents or combined/integrated components. The wireless transceiver440 may be configured to communicate signals (e.g., with the UE 200, oneor more other UEs, and/or one or more other devices) according to avariety of radio access technologies (RATs) such as 5G New Radio (NR),GSM (Global System for Mobiles), UMTS (Universal MobileTelecommunications System), AMPS (Advanced Mobile Phone System), CDMA(Code Division Multiple Access), WCDMA (Wideband CDMA), LTE (Long-TermEvolution), LTE Direct (LTE-D), 3GPP LTE-V2X (PC5), IEEE 802.11(including IEEE 802.11p), WiFi, WiFi Direct (WiFi-D), Bluetooth®, Zigbeeetc. The wired transceiver 450 may include a transmitter 452 and areceiver 454 configured for wired communication, e.g., with the network130 to send communications to, and receive communications from, the TRP300, for example. The transmitter 452 may include multiple transmittersthat may be discrete components or combined/integrated components,and/or the receiver 454 may include multiple receivers that may bediscrete components or combined/integrated components. The wiredtransceiver 450 may be configured, e.g., for optical communicationand/or electrical communication.

The configuration of the server 400 shown in FIG. 4 is an example andnot limiting of the aspects of the disclosure, including the claims, andother configurations may be used. For example, the wireless transceiver440 may be omitted. Also or alternatively, the description hereindiscusses that the server 400 is configured to perform or performsseveral functions, but one or more of these functions may be performedby the TRP 300 and/or the UE 200 (i.e., the TRP 300 and/or the UE 200may be configured to perform one or more of these functions).

FIG. 5 illustrates a flow chart 500 for a UE, such as UE 200, todetermine a confidence level in its location information and use that towarn nearby UEs when there is an SPS spoofing attack and to correct itslocation information that is provided to nearby UEs.

As illustrated, the UE receives SPS signals, which is used to generatelocation information from position engine 235 in FIG. 2, at block 502.The SPS signals may be non-anomalous and thus, the resulting locationinformation at block 502 may include a correct location estimate.Alternatively, the SPS signals may be anomalous, e.g., spoofed, and theresulting location information at block 502 may include an incorrectlocation estimate.

The UE further receives wireless messages from one or more other UEs,e.g., via transceiver 240 shown in FIG. 2, from which the location ofthe transmitting UEs may be determined at block 504. The wirelessmessages may further include the confidence level in the location of thetransmitting UEs and the source of the location estimate, as indicatedin block 504. The wireless messages, by way of example, may be CommonAwareness Messages (CAM), Decentralized Notification Messages (DENM) orBasic Safety Message (BSM), used for, e.g., Advanced Driver AssistanceSystem (ADAS), provided via C-V2X or other types of communications.

As illustrated at block 506, the UE may maintain a cache of its ownlocation information. The cached location information, for example, maybe the last known location, which may be used, e.g., in case of a powerdown. The cached location information may include a previouslydetermined location estimate, which may be derived from SPS information(if reliable) or non-SPS information, such as from information fromnon-SPS sensors, and previously cached location information and locationinformation received from other UEs. The cached location information mayfurther include additional information, such a confidence level in thelocation estimate, an indication of the source of the location estimate,or a combination thereof.

At block 508, the UE may derive location information from non-SPSsensors, such as sensors 213, camera 218, and wireless transceiver 240in FIG. 2. For example, the location information may include IMU data,indicating acceleration, orientation, wheel revolution counts, RADARdata, LIDAR data, image information, etc. The location information mayfurther include location information received from other UEs or anindication that received SPS signals may be unreliable, e.g., which maybe received from other UEs or from a traffic management server, viawireless transceiver 240 in FIG. 2.

At block 510, the UE determines the confidence level in the locationinformation determined using the SPS signals at block 502. The UE, forexample, may determine whether the received SPS signals are anomalous,and thus, the confidence level in the location information determinedusing the SPS signals is correspondingly low. In some implementations,the UE may compare changes in the position and time determined using theSPS signals with information derived from non-SPS information, includingthe cached location information, sensor information, and locationinformation received from other UEs. For example, spoofed SPS signalsmay carry a time that is different from the actual SPS time. Whenspoofing occurs, the difference between the local time, e.g., derivedfrom a local oscillator of the sensors 213 in FIG. 3 and SPS timereceived in the SPS signals may experience a sudden change that is notnormally occurring, and observation of this change may indicateanomalous SPS signals and low confidence in the SPS derived locationestimate.

Additionally, anomalous SPS signals may generate an incorrect locationestimate. Thus, anomalous SPS signals may be detected by determiningthat the location estimate derived from the received SPS signals isincorrect, e.g., based on non-SPS information. For example, a suddenchange in location will necessarily require corresponding signals fromthe non-SPS sensors in the UE, such as a rapid acceleration toaccommodate the sudden change in location, RADAR and LIDAR shouldobserve a rapid change of the surrounding environments, RADAR will haveto detect sudden rise in the doppler signals, steering column sensorwill have to register change in yaw, while wheels sensors will have toregister changes in the vehicle velocity. In the absence ofcorresponding indications of an abrupt location change from the non-SPSsensors, a sudden change in an SPS derived location estimate mayindicate that the SPS signals are anomalous and suspicious, andnecessary remedial steps may be required.

Thus, the SPS derived location estimate may be compared to non-SPSinformation, e.g., from non-SPS sensors, cached location, and locationsreceived from one or more other UEs. In some implementations, thenon-SPS based information that is compared to the SPS derived locationestimate may be another location estimate derived from non-SPS sources,such as non-SPS sensors, cached location, and locations of other UEs,e.g., as determined at block 516. This comparison will allow todetermine confidence level on the estimated location derived from theSPS signals. For example, if the SPS signals are spoofed, there could besignificant difference of location between cached location informationand SPS derived location, which is not consistent with the non-SPSsensor information. Similarly, if the SPS signals are spoofed, the SPSderived location estimate may differ in a noticeable manner from thelocation information received from other UEs.

The confidence level for the SPS derived location estimate may bedetermined based on the magnitudes and types of differences between theSPS derived location estimate and the non-SPS information. By way ofexample, if the non-SPS information and SPS derived location estimatediffer by only small amounts or if data from only a single non-SPSsensor differs, while the remaining non-SPS sensors closely match, thenthe confidence level may be relatively high. In contrast, if thedifferences are large or all non-SPS sensors indicate a significantdifference, then the confidence level may be relatively low. In thedetermination of the confidence level, the data from different ofsensors may be weighted differently. If the SPS derived locationestimate is compared to a non-SPS derived location estimate (e.g.,generated in block 516), the confidence level in the SPS derivedlocation estimate may be high if the location estimates closely match orare within corresponding uncertainty ranges, and conversely may be lowif there is a discrepancy in the location estimates or they are outsidethe uncertainty ranges.

In some implementations, the SPS derived location estimate (from block502) may be continuously compared to cached location information (fromblock 506) and in some implementations to location information from thesensors (from block 508). For example, an SPS derived location estimatemay be generated continuously, e.g., at a rate of 10 Hz, and each SPSderived location estimate may be compared to the previous cachedlocation from block 506. The previous cached location may be updatedbased on estimated movement of the vehicle, e.g., vehicle speed anddirection, obtained from the location information from the sensors(block 508), e.g., dead reckoning. The difference between the SPSderived location estimate and the updated cached location (e.g., deadreckoning position) may be compared to a predetermined threshold todetermine if they adequately match. In some implementations, thepredetermined threshold may be based on the speed of the vehicle. If thecomparison succeeds, a high confidence level, e.g., 0.90, may be setbased on that filter, while if the comparison fails, a low confidencelevel, e.g., 0.20, may be set based on that filter. In someimplementations, the confidence level may be a function of thedifference in the comparison, e.g., multiple predetermined thresholdsmay be used to generate different confidence levels.

In some implementations, additional filtering steps may be performedthat may increase or decrease the confidence level further. For example,if the initial comparison between the SPS derived location estimate andthe updated cached location (e.g., dead reckoning position) fails,additional factors, such as locations derived from other sensors andlocations received from other UEs (from block 504) may be used to modifythe confidence level. For example, the SPS derived location estimate maybe compared to a non-SPS derived location estimate, e.g., determinedusing multilateration based on locations received from other UEs (fromblock 504) and ranges to the other UEs (from block 508) or, e.g., acellular based location estimate, or any other positioning information,e.g., vision based positioning, wireless local area network (WLAN) basedpositioning, wireless personal area network (WPAN) based positioning,etc. In some implementations, the comparison of the SPS derived locationestimate and the non-SPS derived location estimate may be compared to apredetermined threshold (or a number of thresholds) to determine if thematch fails or succeeds and corresponding confidence level. Thethreshold(s), for example, may be based on the speed of the vehicle. Ifthe match(es) in the subsequent filters fail, the confidence level maybe further reduced, or conversely, if the match(es) in the subsequentfilters succeed, the confidence level may be increased.

In some implementations, instead of performing multiple filters, asingle non-SPS derived location estimate may be generated based on allavailable information, e.g., cached location (block 506), sensorinformation (block 508), and location of other UEs (block 504), whichmay be compared to the SPS derived location estimate. The resultingdifference may be compared to one or more thresholds to generate acorresponding confidence level. The thresholds, for example, may bebased on the speed of the vehicle.

Table 1, by way of example, illustrates various confidence levels thatmay be generated based on the comparison of the SPS derived locationestimate and non-SPS derived location information, and relatedexplanations. If desired, other confidence levels may be used, andadditional confidence levels may be included with different actionsundertaken in response to the comparison.

TABLE 1 Confidence level Explanation Confidence <.90 Host vehicle SPSinformation is not reliable, use non SPS location informationConfidence >.90 SPS information is reliable. Use SPS information

At block 512, the confidence level determined at block 510 may becompared to a predetermined threshold, e.g., as illustrated in Table 1.If the confidence level in the SPS derived location estimate is higherthan the predetermined threshold, the UE may transmit locationinformation including the SPS derived location estimate to other UEs,along with source of the location estimate at block 514. In someimplementations, the location information may further include theconfidence level for the location estimate. The message, for example,may be a CAM, DENM, or BSM message that is sent via a C-V2X or othertype of communication. The cached location information at block 506 maybe updated accordingly.

On the other hand, if the confidence level in the SPS derived locationestimate is lower than the predetermined threshold at block 512, the SPSderived location estimate is considered unreliable, and the UE will nottransmit the SPS derived location estimate to other UEs. Instead, the UEmay transmit location information to other UEs that includes a locationestimate determined from non-SPS information.

For example, at block 516, the UE may derive a location estimate usingnon-SPS information, including the cached location information fromblock 506, non-SPS sensor information at block 508 (e.g., using deadreckoning or other position determination techniques), and locationinformation received from other UEs, e.g., at block 504. For example,where location information from a plurality of trusted UEs is received,this crowd sourced information may be used to help estimate the currentlocation of the UE, e.g., using ranging information to the trusted UEsderived using radar, lidar or wireless ranging techniques such as roundtrip time measurements. The location estimate, for example, may bedetermined by the position engine 235 and one or more processors 210implementing the location determination module 282 in FIG. 2. Theconfidence level in the non-SPS derived location estimate may bedetermined, e.g., based on confidence levels of the non-SPS data used,e.g., the confidence level in the cached location information and theconfidence levels in the location information received from other UEs.In some implementations, the confidence level in the non-SPS derivedlocation estimate may be derived in a manner similar to the confidencelevel derived for the SPS derived location estimate, as discussed above.For example, a non-SPS derived location estimate may be generated andcompared to previous cached location, which may be updated based onestimated movement of the vehicle, e.g., vehicle speed and direction,using dead reckoning. The difference may be compared to one or morepredetermined thresholds to determine if they adequately match andcorresponding confidence levels generated. The UE may transmit thelocation information including the non-SPS derived location estimate toother UEs, along with source of the location estimate at block 514. Insome implementations, the location information may further include theconfidence level for the location estimate. The cached locationinformation at block 506 may be updated accordingly.

Additionally, the UE additionally send a message, e.g., to a trafficmanagement server via an RSU or BTS, to provide an indication that thereceived SPS signals are anomalous and are unreliable. The message mayinclude location information, such as non-SPS derived location estimate,and in some implementations, the source of the location estimate andconfidence level, so that the traffic management server may identifywhether the anomalous SPS signals are associated with a specific area orvehicle. The traffic management server, for example, may providewarnings to vehicles in an area if the anomalous SPS signals associatedwith that specific area.

UEs that receive location information from a transmitting UE thatindicates that the source of the location estimate is non-SPSinformation (or otherwise indicate that the SPS derived locationestimate is unreliable) may flag the transmitting UE as transmittingpossibly spoofed or otherwise unreliable location information. Thereceiving UE may discount or weight the location informationaccordingly. Moreover, a UE that receives an indication that the SPSderived location estimate is unreliable may use this information todecrease the confidence level in its own SPS derived location estimate.

FIG. 6 illustrates an example environment 600 in which the UE 200 mayreceive one or more anomalous SPS signals due to various scenarios andmay provide location information to the UE 114 that includes a non-SPSderived position estimate, source of the location estimate, andconfidence level of the location estimate. For example, the SV 183 maysend an anomalous SPS signal 680 to the UE 200. The anomalous SPS signal680 may be anomalous in one or more ways. For example, the signal 680may be a spoofed signal, being produced with a format associated withthe SV 183 but being inaccurate, e.g., having incorrect timing, whichmay lead to an inaccurate determination of the range from the UE 200 tothe SV 183. As another example, the signal 680 may be a spoofed signal,having a format associated with another SV, e.g., another SV of the sameconstellation that contains the SV 183 (i.e., the constellation 180) oranother SV of a different constellation, e.g., of the constellation 190.In this case, a pseudorange determined for the signal 680 may correspondto the range from the UE 200 to the SV 183 but the UE 200 will use thisrange as a range from the UE 200 to the expected location (e.g., asindicated by ephemeris data) of the SV 191. In either of thesescenarios, i.e., inaccurate information in a signal of a format of theSV 183 or simulating a format of another SV, the UE 200 may calculate anincorrect location for the UE 200 if the UE 200 does not recognize thesignal 680 as being anomalous and thus does not take appropriate action,e.g., determining and providing a non-SPS derived location estimate tothe UEs, along with an indication of the source of the locationestimate. The anomalous SPS signal 680 has a carrier frequency, and thecarrier frequency may be a frequency often used by UEs to determinelocation using SPS signals, such as an L1 frequency (1575.42 MHz) of aGPS system. The SV 183 may also send one or more non-anomalous SPSsignals such a non-anomalous SPS signal 683, especially if the anomalousSPS signal 680 was sent due to an operational error of the SV 183. Thenon-anomalous SPS signal 683 may have a different carrier frequency thanthe anomalous SPS signal 680.

As another example of the UE 200 receiving an anomalous SPS signal, theUE 200 may receive one or more anomalous SPS signals 615, 625 fromsatellite signal emulators 610, 620, respectively. The satellite signalemulators 610, 620 may be SPS signal simulators configured to produceand send signals that mimic SPS signals. The anomalous SPS signals 615,625 may thus emulate signals from (e.g., have formats (e.g.,pseudorandom codes) corresponding to) SVs such as the SVs 191, 192,respectively. The anomalous SPS signals 615, 625 may have much higherpower than non-anomalous SPS signals 691, 692 from the SVs 191, 192 whenreceived by the UE 200, which may cause the UE 200 to lock to theanomalous SPS signals 615, 625 over (instead of) the non-anomalous SPSsignals 691, 692 actually sent by the SVs 191, 192.

As discussed, the UE 200 may use one or more other entities in theenvironment 600 to help identify anomalous signals as being anomalous,e.g., by determining consistency or inconsistency of the anomaloussignal with other information. For example, the UE 200 may further usenon-SPS information, such as cached location information, non-SPS sensorinformation, locations of other UEs, or any combination thereof todetermine the reliability of the SPS signals received. For example, theUE 200 may determine that the time derived from SPS signals is notconsistent with the time determined from a local oscillator or otherlocal sources. The UE 200, for example, may determine a non-SPS derivedlocation estimate from the non-SPS information, which may be compared tothe SPS derived location estimate to generate a confidence level. Inanother example, the UE 200 may compare any changes in location tonon-SPS sensor information, such as indications of acceleration, etc.,that should correspond with changes in location. In another example, theUE 200 may be configured to determine a distance to the UE 114 usingsignaling 630 (e.g., radar signals, sonar signals, and/or lidarsignals). The UE 200 may, for example, use this distance information anda location of the UE 114 provided by the UE 114 to the UE 200 to helpdetermine consistency of one or more SPS signals with an approximatelocation of the UE 200. The UE 200 may be configured to use visualinformation (e.g., light rays 642 reflected off a landmark 640) todetermine the approximate location of the UE 200. The UE 200 may, forexample, capture one or more images of the landmark 640 using the camera218, identify the landmark 640, find a location of the landmark 640 in alookup table of landmarks and locations (or by inquiring another entity,such as the server 400, for this information), and using the location ofthe landmark 640 as an approximate location of the UE 200.

If the UE 200 determines that the SPS derived location estimate has alow confidence level, e.g., below a predetermined threshold, the UE maysend location information to the UE 114 (and other UEs), that includesthe non-SPS derived location estimate, the source of the locationestimate (i.e., the non-SPS information), and the confidence level inthe location estimate.

FIG. 7 illustrates a signaling and process flow 700 showing the UE 200receiving one or more anomalous SPS signals and identifying theanomalous SPS signals as anomalous, which may correspond, e.g., toblocks 510 and 512 in FIG. 5. The flow 700 includes the stages shown butis an example only, as stages may be added, rearranged, and/or removed.Also, a limited quantity of SPS signals are shown in order to facilitateunderstanding, but numerous other signals may be received by the UE 200,some of which are discussed.

At stage 710, the UE 200 receives anomalous SPS signals 680, 625 fromthe SV 183 and the satellite signal emulator 620, respectively. Theanomalous SPS signal 680 may, for example, have a format thatcorresponds to the SV 183 but may be in inaccurate in some way (e.g.,timing, power, etc.). As another example, the signal 680 may have aformat of another SV, i.e., an SV other than the source of the signal680, in this example, the SV 183. The anomalous SPS signal 625 may havethe format of an SPS signal corresponding to an SV, in this example, theSV 191.

At stage 720, the UE 200 may perform a sky aperture test to determinewhether a received signal is expected to be received and/or whether areceived signal originated from an expected region of the sky. Forexample, the anomaly detection module 284 may be configured to use anestimate of the location of the UE 200 to determine which SVs should bevisible and/or which SVs should not be visible to the UE 200. Theestimate of the location of the UE 200 may be determined using one ormore of various techniques such as dead reckoning based on a previouslydetermined location, or using a known location of a serving base stationas the estimated location, or another technique. The module 284 may beconfigured to determine expected visibility based on ephemeris data(indicative of current and future SV locations) for one or moreconstellations of SVs and an approximate location of the UE 200. Theapproximate location of the UE 200 may be based, e.g., on a receivedbase station signal and known location of the base station sending thesignal, a previously determined location of the UE and time since thedetermination of that location, etc. The anomaly detection module 284may be configured to identify a signal as anomalous if the signalcorresponds to an SV that should not be visible at the presentapproximate location of the UE 200. Also or alternatively, the anomalydetection module 284 may be configured to determine an approximatedirection (possibly corresponding to a region of the sky) from which areceived signal was sent. For example, the module 284 may use sensorinformation from one or more of the sensor(s) 213 regarding orientationof the UE 200 and an angle of arrival, relative to the UE 200, of areceived signal to determine a region relative to a location of the UE200 from which the received signal originated, i.e., a source region.The source region may be a range of angles relative to a location of theUE 200, e.g., multiple combinations of θ and ϕ in spherical coordinates.The source region may, for example, be a source direction determinedfrom the angle of arrival and orientation of the UE 200, and anuncertainty around the source direction, e.g., such that the sourceregion includes the source direction and any direction within athreshold angle (e.g., 5°) of the source direction. The module 284 maybe configured to determine whether the source region corresponds to(includes) an expected location of an SV (e.g., based on ephemeris data)corresponding to the received signal (e.g., an SV that sends signalswith a same format as a format of the received signal). The module 284may be configured to identify the received signal as an anomalous SPSsignal if the signal did not originate from the expected location of theSV, e.g., if the expected location is not in the determined sourceregion. For the exaggerated example shown in FIG. 6, the module 284 maydetermine that for the anomalous signal 615, the source region (whichwould include the satellite signal emulator 610) does not include the SV191, and thus the module 284 may label the anomalous signal 615 asanomalous.

At stage 730, non-anomalous SPS signals 682, 683, 691, 692 are sent bythe SVs 182, 183, 191, 192 and received by the UE 200. The timing of theSPS signals shown are examples, and SPS signals may be received at timesin addition or instead of the times shown. For example, thenon-anomalous SPS signal 691 may be sent by the SV 191 and received bythe UE 200 before the anomalous SPS signal 615 is sent by the satellitesignal emulator 620 and received by the UE 200. The non-anomalous SPSsignal 683 may, for example, have a different carrier frequency than theanomalous SPS signal 680. The non-anomalous SPS signal 691 may, forexample, have the same carrier frequency as the anomalous SPS signal615. The non-anomalous SPS signals 682, 692 may, for example, have thesame carrier frequencies as the non-anomalous SPS signals 683, 691,respectively.

At stage 740, the UE 200 may perform position determination from non-SPSinformation, such as dead reckoning position determination. For example,the processor 210 may use one or more motion sensor measurements todetermine an amount (and possibly direction) of movement of the UE 200since the time of the previously determined position. The processor 210may be configured to use the determined movement of the UE 200 and oneor more previous SPS signal measurements (e.g., one or more rawmeasurements, such as time of arrival, and/or one or more processedmeasurements, such as pseudorange) to determine one or more expectedpresent SPS signal measurements. For example, processor 210 may beconfigured to use the determined movement (e.g., magnitude anddirection) and a previously determined location of the UE 200 todetermine an approximate present location of the UE 200. The processor210 may be configured to use the approximate present location of the UE200 and a time since the previously determined location was determinedto determine the expected present SPS signal measurement. The processor210 may be configured to trigger a consistency check in response to theexpected present SPS signal measurement differing from a correspondingactual present SPS signal measurement by more than a threshold amount.The threshold may take a variety of forms (e.g., a percentage, aquantity in units of the measurement (e.g., power)) and may have avariety of values.

At stage 750, the UE 200 may check SPS signal consistency to determinewhether an SPS signal is anomalous. The anomaly detection module 284 maybe configured to determine whether there are one or more inconsistenciesregarding one or more SPS signals received by the UE 200 relative to oneor more expectations. An SPS signal inconsistency may be an unexpectedsignal measurement determined, for example, relative to one or moreother SPS signals from the same SV and/or relative to one or more otherSPS signals from one or more other SVs (from the same constellationand/or one or more other constellations), and/or based on a determinedlocation approximation. For example, the anomaly detection module 284may be configured to determine whether an inconsistency exists betweenSPS signals of different bands (carrier frequencies in different bands)and/or between SPS signals of different SVs (intra-constellation and/orinter-constellation). Other examples are possible for determining SPSsignal inconsistency.

The anomaly detection module 284 may be configured to determine whetheran SPS signal has a received power that is inconsistent with one or moreexpectations. For example, the module 284 may be configured to detectthat the received power differs from another received signal power bysignificantly more than an expected amount. The anomaly detection module284 may be configured to determine an actual power difference betweenreceived signals and a corresponding expected power difference anddetermine whether the actual power difference differs from the expectedpower difference by more than a power threshold. The analyzed SPSsignals may correspond to the same SV and may have the same or differentcarrier frequencies, or the analyzed SPS signals may correspond todifferent SVs (within the same constellation or in differentconstellations). For example, the anomaly detection module 284 maydetermine an actual power difference between the anomalous SPS signal615 (from the satellite signal emulator 620) and the non-anomalous SPSsignal 691 (from the SV 191) in response to the anomalous signal 615having a format corresponding to (similar to or identical to) the formatof signals sent by the SV 191, thus giving the appearance that theanomalous signal 615 originated from the SV 191. The anomaly detectionmodule 284 may further determine an expected power difference formultiple SPS signals received from the SV 191. For example, for multipleSPS signals with the same carrier frequency both received from the SV191 within a threshold amount of time of each other, the anomalydetection module 284 may determine (e.g., retrieve from the memory 211)an expected power difference that is very small. The anomaly detectionmodule 284 may determine whether the actual power difference between thesignals 615, 691 differs by more than a power threshold from theexpected power difference. For example, the expected power differencefor signals from the same SV within a small time window may be zero (ornearly zero), and the power threshold may be small, e.g., 1 dB. Becausethe anomalous signal 615 came from the satellite signal emulator 620,the power of the signal 615 may be much higher than the power of thesignal 691, and thus the difference in power between the signals 615,691 may be much higher than 1 dB, in response to which the anomalydetection module 284 may identify the signal 615 as anomalous (and/oridentify the signal 691 as anomalous). Comparing signals over time thatare supposedly from the same SV and have the same carrier frequency mayhelp detect introduction of a spoofed SPS signal. As another example,the anomaly detection module 284 may determine actual and expected powerdifferences for the signals 615, 691, where the signals 615, 691 havedifferent frequencies. In this case, the expected power difference maybe small (e.g., zero or close to zero) and the power threshold may besmall, e.g., 1 dB. Comparing signals from the same SV but with differentfrequencies may help identify spoofed signals as signals may only bespoofed for an SV (or a constellation) for one carrier frequency (or atleast less than all carrier frequencies). As another example, theanomaly detection module 284 may determine actual and expected powerdifferences between the anomalous SPS signal 615 and another SPS signalof another SV, e.g., one of the SPS signals 682, 683, 692. The anomalydetection module 284 may determine the expected power difference basedon ephemeris data for the appropriate SV 182, 183, 192 and anapproximate location of the UE 200. The power threshold may depend onthe expected power difference, or may be independent of the powerdifference, e.g., being a percentage or amount of decibels. Comparingsignals from different SVs may help identify spoofed signals as signalsmay only be spoofed for one constellation (or at least less than allconstellations). For example, if the UE 200 is indoors, all SPS signalswill typically be received with very low power if at all, but spoofedSPS signals may be received with much higher power than the actual SPSsignals, and with adequate power for location determination. The SVs maybe selected based on their visibility to the UE 200 and/or theirrelative position in the sky. For example, the anomaly detection module284 may select SPS signals for SVs that are close enough to each otherthat the attenuation and/or multi-path effects for the SPS signals fromthe SVs are likely to be similar, e.g., such that the expected powerdifference will be near zero.

Received power inconsistency over time and/or between SVs (e.g., betweenconstellations) may be particularly helpful in identifying indoor SPSsignal spoofing. For example, if the anomaly detection module 284determines that an SPS signal from an SV in one constellation, e.g., theSV 181 in the constellation 180, decreases in power (e.g., due to the UE200 moving from being outdoor to indoor) but that the received powerfrom an SPS signal purportedly from another SV of another constellation,e.g., the SV 191 of the constellation 190, increases or at least doesnot decrease similarly to the power decrease of the SPS signal from theSV 181, then the anomaly detection module 284 may identify the SPSsignal from the SV 191 as anomalous. The anomaly detection module 284may be configured to analyze the SPS signals from multiple SVs ofmultiple constellations such that the anomaly detection module 284 mayidentify SPS signals of one constellation as anomalous where thereceived power of these SPS signals do not decrease in power nearly asmuch as (or even increase in power relative to) the received power ofmultiple SPS signals from another constellation.

The anomaly detection module 284 may be configured to determine whetheran SPS signal has a corresponding pseudorange that is inconsistent withexpectation. For example, the anomaly detection module 284 may beconfigured to determine that a pseudorange to an SV based on atime-filtered location determination differs by more than a pseudorangethreshold relative to a pseudorange determined using an SPS signalpurportedly from that SV. The anomaly detection module 284 may use afilter result (e.g., a Kalman filter result) for a location of the UE200 to determine an expected pseudorange to an expected location of anSV based on ephemeris data. The anomaly detection module 284 maydetermine measured pseudorange to the SV based on a measured SPS signalcorresponding to the SV (e.g., having a format of signals from the SV).The anomaly detection unit may identify the measured SPS signal asanomalous if the expected pseudorange differs from the measuredpseudorange by more than the pseudorange threshold, e.g., 1%, or 5%, or10%. This may help identify a signal from an SV of one constellationthat emulates a signal from another constellation as anomalous. Asanother example, the anomaly detection module 284 may be configured todetermine that a pseudorange based on received (actual or spoofed) SPSsignals purportedly from the same SV deviates from an expectation bymore than a pseudorange threshold. For example, the anomaly detectionmodule 284 may identify a change in pseudorange of more than 1% or morethan 5% or more than 10% between pseudorange determinations to indicatethat the SPS signal corresponding to the later pseudorange determinationis anomalous. The value of the pseudorange threshold may be a functionof the time between reception of the SPS signals corresponding to thepseudoranges being compared (e.g., with the pseudorange threshold havinga higher value (e.g., a higher percentage) the longer the time betweensignal reception leading to the pseudoranges being compared). As anotherexample, the anomaly detection module 284 may be configured to determinewhether a pseudorange difference based on measured SPS signals differsby more than a threshold amount from an expected amount. Similar to thediscussion above with respect to power differences, the anomalydetection module 284 may determine a measured pseudorange differencebased on measured signals, e.g., the anomalous signal 615 and thenon-anomalous signal 692, and determine an expected pseudorangedifference to the corresponding SVs 191, 192 (e.g., based on anapproximate location of the UE 200 and ephemeris data for the SVs 191,192), and identify at least one of the signals 615, 691 as anomalous ifthe difference between measured pseudorange difference and the expectedpseudorange difference differ by more than a threshold amount, e.g., 1%,5%, 10%.

The anomaly detection module 284 may select which SPS signals to use toperform a consistency check, e.g., to determine received powerdifferences and/or pseudorange differences. For example, the anomalydetection module 284 may be configured to select one or more SPS signalscorresponding to one or more respective SVs based on a priority of SVsand/or constellations. The anomaly detection module 284 may, forexample, select SPS signals for SVs based on levels of trust for the SVsand/or constellations, and/or based on one or more other criteria. Forexample, a native SPS (i.e., an SPS owned by a country associated withthe UE 200) may be given a highest level of trust. For example, GPS maybe given highest trust (relative to other SPSs) by a UE associated with(e.g., believed to be presently in, or purchased in) the United Statesof America, Galileo by a UE associated with Europe, Beidou by a UEassociated with China, and GLONASS by a UE associated with Russia.Non-native SPSs may be given lower trust, e.g., in a hierarchy of trustthat may depend, for example, on the native SPS. The UE 200 may use theSPSs in order of trust, for example, using the most trusted SPS or thetwo most trusted SPSs to determine an approximate location of the UE200, and use this approximate location to check consistency with one ormore of the remaining SPSs.

At stage 760, the UE 200 receives a base station signal 765 from the TRP300 (e.g., one or more of the base stations 120-123 or another basestation). The base station signal 765 may include a positioning signal(e.g., a PRS) and/or a communication signal.

At stage 770, the base station signal 765 may be used by the anomalydetection module 284 detect consistency between the base station signal765 and one or more SPS signals. For example, the anomaly detectionmodule 284 may be configured to use the base station signal 765 from theTRP 300 (e.g., from the BTS 120 or the BTS 123 as shown in FIG. 6) todetermine an approximate location of the UE 200. The module 284 may beconfigured to use the approximate location to determine one or moreexpected received powers of one or more SPS signals and/or to determineone or more expected pseudoranges to one or more SVs. The module 284 maybe configured to determine whether the expected received power(s) and/orthe expected pseudorange(s) is(are) consistent with measured receivedpower(s) and/or pseudorange(s) determined from a measured SPS signal ormeasured SPS signals. For example, the module 284 may determine whethermeasured and expected received powers differ by less than a powerthreshold and/or whether measured and expected pseudoranges differ byless than a pseudorange threshold.

At stage 780, the UE 200 may perform a consistency check using one ormore other technologies, i.e., non-SPS technologies. For example, theanomaly detection module 284 may be configured to obtain locationinformation based on radar, Lidar, WAN, and/or Wi-Fi technologies assuch information is available. The anomaly detection module 284 may beconfigured to use the location information obtained by one or more ofthese other technologies to determine whether a location of the UE 200according to such information is consistent with one or more SPSsignals, e.g., consistent with received power level and/or determinedpseudorange or location. For example, the anomaly detection module 284may obtain an approximate location using the signaling 630 (e.g., radar,lidar, sonar) between the UE 200 and the UE 114 to determine theapproximate location of the UE 200 based on a location of the UE 114 anda distance between the UE 114 and the UE 200. As another example, theanomaly detection module 284 may use visual information to determine theapproximate location of the UE 200, e.g., by using visual information torecognize the landmark 640 and use a location of the landmark (e.g.,either stored in the memory 211, provided by the landmark 640, orprovided by another entity such as the server 400) as the approximatelocation of the UE 200. The anomaly detection module 284 may combinetechnologies, e.g., using visual information of the landmark to identifythe landmark and obtain the location of the landmark, using radar todetermine a distance from the landmark, and using this distance and thelandmark location to determine the approximate location of the UE 200.As another example, the anomaly detection module 284 may use informationregarding constraints on the location of the UE 200 to help identify SPSsignals as anomalous. For example, the anomaly detection module 284 mayuse map information and information as to characteristics of the UE 200and/or a vehicle in which the UE 200 resides. Thus, for example, theanomaly detection module 284 may compare determined location and/orpseudorange corresponding to an SPS signal to identify an SPS signal asanomalous that indicates that the UE 200 is in an impossible (or atleast highly unlikely) location, such as on land if the UE 200 is (orresides in) a boat, is in water if the UE 200 is (or resides in) a landvehicle such as car or truck, is displaced significantly from traintracks if the UE 200 is (or resides in) a train, etc. As anotherexample, the UE 200 may check with one or more other UEs withincommunication range to determine whether a location determined by theother UE(s) corresponds to an SPS signal measurement obtained by the UE200. For example, the UE 200 may request a location of another UE and/ormay receive a notification (e.g., a safety notification) pushed byanother UE (e.g., the UE 114 shown in FIG. 6) that indicates a locationof the other UE. The UE 200, e.g., the anomaly detection module 284 maydetermine whether the location indicated by the notification or providedin response to the request is consistent with an SPS signal measurement(e.g., pseudorange, location (e.g., a time-filtered location), etc.)obtained by the UE 200 from a received SPS signal to determine whetherthe received SPS signal is anomalous.

The anomaly detection module 284 may be configured to re-perform one ormore consistency checks of stage 750, and/or to perform one or more ofthe consistency checks of stages 770, 780. The anomaly detection module284 may be configured to perform such checks for every signal or basedon one or more criteria such as every Nth SPS signal or in response toidentifying an SPS signal as anomalous at stage 750. The anomalydetection module 284 may be configured to perform different consistencychecks and/or different amounts of consistency checks based on asensitivity level of knowledge of the location of the UE 200. Forexample, the anomaly detection module 284 for a smartphone may beconfigured not to perform consistency check beyond SPS signal checkingat stage 750 for an exercise application, but the anomaly detectionmodule 284 for a military aircraft may be configured to perform everyconsistency check for which information is available. Checking, andre-checking, consistency of an anomalous SPS signal may help confirm orcontradict the initial identification of an SPS signal as anomalous. Ifan SPS signal is identified as anomalous but subsequent consistencychecking reveals that the SPS signal is consistent with one or moreother SPS signals and/or other forms of consistency checking, then theSPS signal may be re-identified as not anomalous.

At stage 790, the anomaly detection module 284 may send a message toserver 400, which may be a traffic management server, to provide anindication that the received SPS signals are anomalous and areunreliable. The message may include location information, such asnon-SPS derived location estimate, and in some implementations, thesource of the location estimate and confidence level, so that thetraffic management server may identify whether the anomalous SPS signalsare associated with a specific area or vehicle. The traffic managementserver, for example, may provide warnings to vehicles in an area if theanomalous SPS signals associated with that specific area.

FIG. 8 illustrates a signaling and process flow 800 showing the UE 200receiving SPS signals, determining whether the SPS signals are anomalousand sending location information to other UEs that include a locationestimate and source of the location estimate, and in someimplementations, the confidence level in the location estimate. The flow800 includes the stages shown but is an example only, as stages may beadded, rearranged, and/or removed. Also, a limited quantity of SPSsignals are shown in order to facilitate understanding, but numerousother signals may be received by the UE 200, some of which arediscussed.

At stage 810, non-anomalous SPS signals are sent by the SVs 181, 182,183 and received by the UE 200.

At stage 815, the UE 200 may receive anomalous SPS signals from thesatellite signal emulator 620. The anomalous SPS signal may, forexample, have a format that corresponds to the SV 183 but may be ininaccurate in some way (e.g., timing, power, etc.). The timing andnumber of the SPS signals shown are examples, and additional ordifferent SPS signals may be received at times in addition or instead ofthe times shown. For example, the non-anomalous SPS signal may be sentby the SVs and received by the UE 200 after the anomalous SPS signal issent by the satellite signal emulator 620 and received by the UE 200.The anomalous SPS signals may have the same or different carrierfrequency as some or all of the non-anomalous SPS signals.

At stage 820, the UE 200 may determine an SPS based location estimateusing received SPS signals from stage 810 and the anomalous SPS signalsreceived at stage 815 (if any). The processor 210 may be configured touse SPS signal measurements, such as time of arrival, and/or one or moreprocessed measurements, such as pseudorange, to determine an SPS derivedestimated location for the UE 200.

At stage 830, the UE 200 receives wireless messages from one or moreother UEs 114, e.g., via transceiver 240 shown in FIG. 2, that includethe location estimate of each transmitting UE, the source of thelocation estimate (e.g., whether the location estimate is derived fromSPS signals or from non-SPS signals), and the confidence level of thelocation estimate. The wireless messages may be V2X or other types ofmessages, e.g., used for ADAS, such as CAM, DENM, or BSM. The UE 200 mayfurther receive a message broadcast by a traffic control server, whichmay indicate whether anomalous SPS signals have been reported in thearea of the UE 200.

At stage 832, the UE 200 may acquire data input from non-SPS basedsensors, such as IMU sensors, cameras, wireless transceivers, etc. Thedata input, for example, may include data related to acceleration,orientation, velocity, wheel revolution counts, radar data, lidar data,image information, etc. It should be understood, of course, that thesensor input data is not necessarily acquired at one particular moment,but may be acquired continuously over time as the data becomesavailable.

At stage 834, the UE 200 acquires its cached location data, e.g., one ormore previous location estimates stored by UE 200. The location data mayinclude the source of the location estimate (e.g., whether the locationestimate is derived from SPS signals or from non-SPS signals), and theconfidence level of the location estimate.

At stage 840, the UE 200 may determine a non-SPS derived locationestimate, e.g., using non-SPS information, such as the cached locationinformation, sensor data, and location information received from otherUEs, e.g., as discussed in reference to FIG. 5. For example, theprocessor 210 may further be configured to use one or more sensormeasurements to determine an amount (and possibly direction) of movementof the UE 200 since the time of a cached location estimate, e.g. usingdead reckoning. The processor 210 may further be configured to uselocation information from other UEs, if reliable, to assist indetermining a location estimate, e.g., using ranging information to theother UEs, derived from radar, lidar, or wireless ranging techniques,such as round trip time measurements. The processor 210 may beconfigured to use the confidence levels associated with cached locationinformation and the location information from other UEs to assist inposition determination, e.g., by weighting reliable information morethan unreliable information, and to determine the confidence level ofthe determined location estimate.

At stage 850, the UE 200 determines whether the received SPS signals arereliable, e.g., as discussed in FIG. 5 and FIG. 7. For example, the UE200 may determine a confidence level in the SPS derived locationestimate. For example, confidence level in the SPS derived locationestimate may be determined as discussed in FIGS. 5, 6 and 7. Theprocessor 210 may be configured to use movement of the UE 200 determinedfrom the sensors, the cached location input, locations of other UEs, ora combination thereof, to determine whether the SPS derived locationestimate is reliable. For example, the local time for the UE 200, e.g.,derived from a local oscillator or from BTSs via wirelesscommunications, may be compared to the SPS time derived from the SPSsignals. In another example, the SPS derived location estimate may becompared to cached location information or locations of the other UEs.In another example, changes in position of the UE 200, e.g., based onthe difference between the SPS derived location estimate and theprevious location estimates from the cached location information, may becompared to sensor information, such as acceleration data, orientationdata, etc. In another example, the SPS derived location estimate may becompared to the non-SPS derived location estimate. The processor 210 maybe configured to determine a confidence level for the SPS derivedlocation estimate based on the magnitude of its variations with respectto expectations and source of the variations. The processor 210 may beconfigured to determine reliability of the SPS signals, e.g., based oninformation received from other UEs, e.g., in stage 830, such as thesource of location information, confidence level of location estimate,or a warning that received SPS signal are determined to be anomalous.The processor 210 may be configured to determine a confidence levelusing a single filter, e.g., deriving a single non-SPS derived locationestimate from all available non-SPS location information at stage 840,that is compared to the SPS derived location estimate, or in multiplefilters, e.g., deriving a first non-SPS derived location estimate (e.g.based on cached location information and speed and directioninformation) at stage 840, to generate an initial confidence level atthe update rate of the SPS position fix, and if the confidence level islow to derive additional location information, such as a second non-SPSderived location estimate (e.g. based on other UE location informationand sensor information) at stage 840, to update (i.e., increase ordecrease) the confidence level.

At stage 860, the UE 200 selects the SPS derived location or the non-SPSderived location based on the reliability of the SPS signals. Forexample, the processor 210 may be configured to check the confidencelevel against a predetermined threshold. If the confidence level isbelow the threshold (indicating low confidence), the processor 210 mayselect the non-SPS derived location estimate, and if the confidencelevel is above the threshold (indicating high confidence), the processor210 may select the SPS derived location estimate.

At stage 870, the UE 200 sends wireless messages to one or more otherUEs 114, e.g., via transceiver 240 shown in FIG. 2, that include theselected location estimate, the source of the location estimate (e.g.,whether the location estimate is derived from SPS signals or fromnon-SPS information, and in some implementations, the type of non-SPSinformation). In some implementations, the confidence level of thelocation estimate may also be sent. The wireless message may be C-V2X orother types of messages, e.g., used for ADAS, such as CAM, DENM, or BSM.If the UE 200 selects non-SPS derived location estimate, the UE 200 mayfurther send a message to a traffic control server, to indicate thatanomalous SPS signals have been detected by the UE 200, and may includethe location information, e.g., non-SPS derived location estimate,source of the location estimate, and the confidence level of thelocation estimate.

FIG. 9 illustrates a wireless communication system 900 illustrating UEs902 and 904 (illustrated as vehicles) transmitting a wireless locationinformation message to provide a location estimate for the UE as well asthe source of the location information to other one or more otherentities. As illustrated in FIG. 9, the UE 902 may wireless communicatewith other entities, such as UE 904 (illustrated as another vehicle) viacommunication link 903, UE 910 (illustrated as an RSU) via communicationlink 907, and a UE 912 (held by pedestrian 914) via a communication link913. The UE 904 is illustrated as also wirelessly communicating with UE910 via a communication link 915. The communications may be directcommunications using any suitable signaling, such as PC5 interface,e.g., DSRC or C-V2X, or may be indirect communications usinginfrastructure such as RSU 910 or via Uu interface, mmWave or anywireless connection using base stations (e.g., as illustrated in FIG.1).

FIG. 9 illustrates UE 902 transmitting a location information message920 to UE 904, which may likewise be sent to UE 910 and UE 912, e.g.,using broadcast, multicast or unicast transmissions. Moreover, thevarious UEs 904, 910 and 912 may provide similar location informationmessages to UE 902 and to each other, e.g., as illustrated by locationinformation message 921 sent from UE 904 to UE 910, which may also besent to UE 902 via communication link 903. The location informationmessages 920 and 921, for example, may be the same as the messages sentat stages 830 and 870 in FIG. 8. Location information message 921 mayhave the same format as location information message 920, although thecontent of the location information messages 920 and 921 are specificfor the UEs 902 and 904, respectively.

In some implementations, the location information message 920 may bedivided into two or more parts, including a first part 922 that includesthe location estimate determined for the UE 902, and a second part 924that includes a source of the location information used to derive thelocation estimate. The location information message 920 may furtherinclude a third part 926 that provides a determined confidence level forthe location estimate. The location information message 920 may furtherinclude a fourth part 928 that indicates that the received SPS signalswere determined to be anomalous (e.g., the UE 902 is under SPS spoofingattack).

For example, the various parts 922, 924, 926, and 928 of the locationinformation message 920 may be different information elements (IEs). TheIE 924 may indicate the source of the location information used togenerate the location estimate in IE 922. The source of the locationinformation in IE 924 may simply identify whether the source of thelocation information is SPS or non-SPS. In other implementations, thesource of the location information in IE 924 may identify the type ofinformation used to generate the location estimate, such whether thesource is from SPS signals, cellular signals, local area network (LAN)signals, sidelink signals (e.g., from other UEs or RSUs), timedifference of arrival (TDOA), angle of arrival (AoA), and receivedsignal strength (RSS). In some implementations, the IE 924 may include amultibit value that is used to identify the type of source of locationinformation from an enumerated list of sources. Table 2, by way ofexample, illustrates an application-layer IE that may provide thepositional source using enumerated values, that may be included in thesource IE 924 of the location information message 920. Of course, othersources may be enumerated as appropriate.

TABLE 2 Data Element (DE) Description PositionLocationSourcePositionLocationSource ::= ENUMERATED { Unavailable (0), SPS (1), --SPSbased position Cell (2), --Cell Site based position TDOA (3), --TDOAbased position AOA (4), --AOA based position RSS (5), --Received SignalStrength based position LAN (6), --LAN based position SL (7), --Sidelinkbased position Hybrid (8), --Non-SPS hybrid based position } —Encoded asa 3 bit value

In some implementations, the source IE 924 in the location informationmessage 920 may indicate the source of the location information using abinary variable, e.g., as SPS or non-SPS. Table 3, by way of example,illustrates an application-layer IE that may provide the positionalsource as SPS or non-SPS, that may be included in the source IE 924 ofthe location information message 920.

TABLE 3 Data Element (DE) Description PositionLocationSourcePositionLocationSource ::= CHOICE { SPS Non-SPS . . . }

The receiving UE 904 (or any of UEs 910 and 912) may use the source ofthe location information in the location information message 920 toassist in their own location determination and determination of whetherreceived SPS signals may be anomalous. For example, if the UE 904receives location information messages from multiple sources, where someof the location information messages indicate the source of the locationinformation is SPS signals, while other location information messagesindicate the source of the location information is SPS signals, then theUE 904 may select to use location estimates from other UEs which aresourced from SPS signals for assistance in location determination. TheUE 904, for example, may use location estimates from other UEs which aresourced from SPS signals as a filter to verify whether SPS signalsreceived by the UE 904 may be anomalous (e.g., as discussed in FIG. 5),and may determine a location estimate using received SPS signals if theSPS signals are determined to be reliable, and otherwise to use non-SPSinformation (such as the location estimates from other UEs which aresourced from SPS signals and ranges to the other UEs e.g., in sidelinkpositioning, or a previous cached location and sensor information, e.g.,dead reckoning. Moreover, if multiple other UEs report that their sourceof location information is non-SPS based information, the UE 904 may betriggered to check the validity, or to decrease the confidence level, inits own SPS derived location estimate. Thus, the source of the locationinformation from other UEs, may be used for autonomousdriving/cooperative driving use cases.

Additionally, the location information message 920 may include an IEthat includes the confidence level for the location estimate, which maylikewise be used for determining a location estimate and determining aconfidence level in the location estimate, as discussed above, e.g., inFIG. 5.

Additionally, if a UE 902 has determined that it is under an SPSspoofing attack (or otherwise receiving anomalous SPS signals thatcannot be relied upon), the UE 902 may include an IE 928 in the locationinformation message 920 warning that its received SPS signals areunreliable. The indication of unreliable SPS signals (e.g., due to SPSspoofing attack or other anomalous signals) may be provided to otherUEs, e.g., UE 904, which may use the warning to reduce the chance ofmis-identifying the UE 902 as a “rogue” vehicle, and may trigger its ownvalidation of SPS signals. An indication of unreliable SPS signals maybe explicitly provided by the UE 902 as a separate IE 928, e.g., as asingle bit, or may be implicitly provided when the position locationsource IE 924 indicates that the source of location information isnon-SPS.

As illustrated in FIG. 9, a traffic server 930 may be present andconnected to RSU 910 via communication link 932, e.g., which may be abackhaul link 911 or a wireless connection via a network 130 asillustrated in FIG. 1. The traffic server 930, for example, may be aspectrum misbehavior authority that may be used to collect reports of,e.g., V2X, misbehavior reports in order to detect unauthorized use of alicensed band. Latency, however, is an issue when relying on acentralized authority for identification of RF issues. For example, forsafety applications and advance applications such as cooperativedriving, delays in obtaining information related to RF issues ormisbehaviors are undesirable. Accordingly, in some implementations, anRSU 910 (or other sidelink UEs) may be used to identify signalmisbehaviors.

In one implementation, an RSU 910 may be used to detect unreliable SPSsignals based on the location information messages provided by one ormore UEs. For example, the RSU 910 may receive location informationmessages 920 and 921 from UEs 902 and 904 and may determine from thecontent of one or more of the location information messages 920 and 921whether the SPS signals in the area of the RSU 910 are unreliable. TheRSU 910 may report the presence of unreliable SPS signal to a competentauthority, e.g., as illustrated traffic server 930 and/or to UEs 902 and904.

FIG. 10 illustrates a signaling and process flow 1000 showing detectionof unreliable SPS signals by a UE 1002 based on location informationmessages received from UEs 1006-1, 1006-2, 1006-3 (sometimescollectively referred to as UEs 1006). The UE 1002 may be an RSU, andmay be referred to herein as RSU 1002, but may be another V-UE, sidelinkUE, pedestrian held UE, or a smart device. The UEs 1006, for example,may be the same as UE 200 and may each individually determine whetherreceived SPS signals are anomalous and send location information toother UEs and the RSU 1002. The flow 1000 includes the stages shown butis an example only, as stages may be added, rearranged, and/or removed.Also, a limited quantity of UEs 1006 and SPS signals are shown in orderto facilitate understanding, but numerous other signals and UEs may beincluded.

At stage 1010, non-anomalous SPS signals are sent by the SVs 181, 182,183 and received by the UE 1006.

At stage 1015, the UE 1006 may receive anomalous SPS signals from thesatellite signal emulator 620. The anomalous SPS signal may, forexample, have a format that corresponds to the SV 183 but may be ininaccurate in some way (e.g., timing, power, etc.). The timing andnumber of the SPS signals shown are examples, and additional ordifferent SPS signals may be received at times in addition or instead ofthe times shown. For example, the non-anomalous SPS signal may be sentby the SVs and received by the UE 1006 after the anomalous SPS signal issent by the satellite signal emulator 620 and received by the UE 1006.The anomalous SPS signals may have the same or different carrierfrequency as some or all of the non-anomalous SPS signals.

At stage 1020, the UEs 1006 may determine whether the received SPSsignals are anomalous and select to use SPS signals or non-SPSinformation for a location estimate as described, e.g., in stages820-860 in FIG. 8, and elsewhere herein.

At stage 1030, the RSU 1002 may be configured to receive wirelessmessages, e.g., via transceiver 240 shown in FIG. 2, from UEs 1006 thatinclude the selected location estimate and the source of the locationestimate (e.g., whether the location estimate is derived from SPSsignals or from non-SPS signals). The messages sent in stage 1030, forexample, may be similar to stage 870 shown in FIG. 8. In someimplementations, the messages may further include the confidence levelof the location estimate and/or an indication of whether the receivedSPS signals were detected to be anomalous. The wireless message may beV2X or other types of messages, e.g., used for ADAS, such as CAM, DENM,or BSM.

At stage 1040, the processor 210 in an RSU 1002 may be configured todetermine whether the SPS signals are reliable, based on one or moremessages received from the UEs 1006.

The RSU 1002, for example, may determine from one or more locationinformation messages 1030 whether the SPS is reliable or unreliable inthe area around RSU 1002 (e.g., an area within wireless range to the RSU1002 by UEs 1006). For example, in some implementations, the RSU 1002may determine from the source of information in the location informationmessages 1030 whether the location estimate is derived from SPS signalsor from non-SPS signals. If a large number of vehicles are generatinglocation estimates based on non-SPS signals, the RSU 1002 may determinethat the SPS signals in the area around the RSU 1002 are unreliable. Forexample, if the number of UEs that are deriving location estimates basedon non-SPS signals (within a predetermined time period) is greater thana predetermined threshold, the SPS signals may be determined to beunreliable. The number of UEs, for example, may be a percentage of UEssending location information messages, e.g., if the percentage of UEsthat are deriving location estimates based on non-SPS signals (within apredetermined time period) is greater than a predetermined threshold,the SPS signals may be determined to be unreliable.

In some implementations, the RSU 1002 may determine from the confidencelevel for the location estimate whether the SPS signals in the area arereliable or not reliable. For example, if a number of location estimatesin the location information messages 1030 are derived from SPS signals,but the confidence levels for the location estimates are low, the SPSsignals in the area of the RSU 1002 may be determined to be unreliable.A threshold number of low confidence levels may be used, wherein if anumber of location estimates having a low confidence level is greaterthan the threshold, the SPS signals may be identified as unreliable.Different thresholds or weighting may be used for different levels ofconfidence. The RSU 1002 may determine reliability of the SPS signals inthe area based on both the source of information and the confidencelevel. For example, if a number of location estimates are derived fromnon-SPS signals and if a number of the remaining location estimatesderived from SPS signals are assigned low confidence levels, the RSU1002 may determine that the SPS signals in the area are unreliable.

In some implementations, the RSU 1002 may determine from indications inthe location information messages 1030 that received SPS signals weredetermined by the UE to be anomalous whether the SPS signals in the areaare reliable or not reliable. For example, if a number of vehicles aresending location information messages warning that received SPS signalswere determined to be anomalous, the RSU 1002 may determine that the SPSsignals in the area around the RSU 1002 are unreliable. In someimplementations, the receipt of a single indication warning thatreceived SPS signals were determined to be anomalous may be sufficientto determine the SPS signals in the area are unreliable, and in otherimplementations, a greater number or a threshold percentage of UEs maybe required.

At stage 1050, the RSU 1002 may be configured to send wireless messages,e.g., via transceiver 240 shown in FIG. 2, to one or more UEs 1006(e.g., UEs in wireless range) with an indication that the SPS signalsignals in the area are not reliable when the SPS signals have beendetermined to be unreliable in stage 1040. For example, the messageprovided to UEs 1006 may be transmitted via Wave Service Advertisement(WSA) or other channel, and may provide implicitly or explicitly asuggestion to use non-SPS signals for deriving location estimates.

At stage 1055, the RSU 1002 may be configured to send a message, e.g.,via transceiver 240 or transceiver 250 shown in FIG. 2, to the trafficserver 1004 with an indication that the SPS signal signals are notreliable when the SPS signals in the area within wireless range of theRSU 1002 have been determined to be unreliable.

Referring to FIG. 9, in another implementation, an RSU 910 may be usedto identify unreliable or anomalous SPS signals based on the locationinformation messages provided by one or more UEs. For example, in someimplementations, where the UEs 902 and 904 do not determine whether theSPS signals are anomalous, but provide the RSU 910 with an SPS basedlocation estimate, a few or all of the UEs within the range of the RSU910 may receive anomalous SPS signals may be unaware that the SPSsignals are anomalous. Thus, the UEs may send incorrect locationestimates based on the anomalous SPS signals. Accordingly, the RSU 910may determine whether the SPS signals in the area of the RSU areunreliable, e.g., based at least on the location estimates. For example,the RSU 910 may compare distances between location estimates for UEpairs to ranges between UE pair, e.g., provided by the UEs in thelocation information messages 920 and 921. Discrepancies betweenestimated locations and ranges of the UEs may be used to identifyunreliable SPS signals in the area. The RSU 910 may report the presenceof unreliable SPS signal to a competent authority, e.g., as illustratedtraffic server 930 and/or to UEs 902 and 904.

FIG. 11 illustrates a signaling and process flow 1100 showingidentification of unreliable or anomalous SPS signals by a UE 1102 whenbased on the location information messages received from UEs 1106-1,1106-2, 1106-3 (sometimes collectively referred to as UEs 1106). The UE1102 may be an RSU, and may be referred to herein as RSU 1102, but maybe another V-UE, sidelink UE, pedestrian held UE, or a smart device. TheUEs 1106, for example, may be the same as UE 200, but may notindividually determine whether received SPS signals are anomalous. Theflow 1100 includes the stages shown but is an example only, as stagesmay be added, rearranged, and/or removed. Also, a limited quantity ofUEs 1106 and SPS signals are shown in order to facilitate understanding,but numerous other signals and UEs may be included.

At stage 1110, non-anomalous SPS signals are sent by the SVs 181, 182,183 and received by the UE 1106.

At stage 1115, the UE 1106 may receive anomalous SPS signals from thesatellite signal emulator 620. The anomalous SPS signal may, forexample, have a format that corresponds to the SV 183 but may be ininaccurate in some way (e.g., timing, power, etc.). The timing andnumber of the SPS signals shown are examples, and additional ordifferent SPS signals may be received at times in addition or instead ofthe times shown. For example, the non-anomalous SPS signal may be sentby the SVs and received by the UE 1106 after the anomalous SPS signal issent by the satellite signal emulator 620 and received by the UE 1106.The anomalous SPS signals may have the same or different carrierfrequency as some or all of the non-anomalous SPS signals.

At stage 1120, the UEs 1106 may determine location estimates based onreceived SPS signals, including the spoofed SPS signals from stage 1115.The UEs 1106 may additionally determine ranges to other nearby UEs usingRADAR sensors, LIDAR sensors, and/or well-known wireless rangingtechniques (WAN, and/or Wi-Fi technologies), such as round trip timemeasurements.

At stage 1130, the RSU 1102 may be configured to receive wirelessmessages, e.g., via transceiver 240 shown in FIG. 2, from UEs 1106 thatinclude the SPS based location estimate and may include the ranges toother UEs. Because the UEs 1106 do not determine whether the receivedSPS signals are anomalous in the present implementation, the messages instage 1130 may not include the source of the information or confidencelevel associated with the location estimate. The wireless message may beV2X or other types of messages, e.g., used for ADAS, such as CAM, DENM,or BSM.

At stage 1140, the processor 210 in an RSU 1102 may be configured todetermine whether the SPS signals are reliable, based on one or moremessages received from the UEs 1106.

The RSU 1102, for example, may determine whether SPS signals arereliable or unreliable in the area around RSU 1102 (e.g., an area withinwireless range to the RSU 1102 by UEs 1106), e.g. based at least on thelocation estimates received in the messages in stage 1130. As discussedherein, for example, the RSU 1102 may check the consistency of thelocation estimates for each UE over time. If the location estimates fora UE, for example, change in a manner that is inconsistent with expectedmovement of the UEs (e.g., vehicles moving sidewise or backwards one afreeway), the RSU 1102 may determine that the SPS signals areunreliable. Additionally or alternatively, the RSU 1102 may check theconsistency of the estimated positions with respect to the rangesprovided in the messages 1130. For example, the RSU 1102 may determinethe distances between UE pairs based on their location estimatesprovided in messages 1130 and may compare the distances to the rangesbetween the UEs provided in the messages 1130. The RSU 1102 maydetermine whether the SPS signals are reliable based on the comparisonof the distances to the ranges for one or more pair of UEs.

At stage 1150, the RSU 1102 may be configured to send wireless messages,e.g., via transceiver 240 shown in FIG. 2, to one or more UEs 1106(e.g., UEs in wireless range) with an indication that the SPS signalsignals in the area are not reliable when the SPS signals have beendetermined to be unreliable in stage 1140. For example, the messageprovided to UEs 1106 may be transmitted via Wave Service Advertisement(WSA) or other channel, and may provide implicitly or explicitly notifyvehicles to check the location information fidelity or recommend tochange the source of the location information used to determining alocation estimate.

At stage 1155, the RSU 1102 may be configured to send a message, e.g.,via transceiver 240 or transceiver 250 shown in FIG. 2, to the trafficserver 1104 with an indication that the SPS signal signals are notreliable when the SPS signals in the area within wireless range of theRSU 1102 have been determined to be unreliable.

Accordingly, the detection of anomalous SPS signals may be offloaded tothe RSU, which may have access to a more diverse source of information,e.g. from various UEs, than any one UE. Moreover, latency may be reducedby using an RSU for identification of anomalous SPS signals, compared tothe use of a remote traffic server, and the RSU may provide the usefulinformation to the traffic server.

FIG. 12 is a flow chart 1200 illustrating a method of transmittinglocation information by a user equipment (UE), such as UE 200.

At block 1202, the UE receives SPS signals (Satellite Positioning Systemsignals), e.g., as discussed in FIG. 5, stages 710 and 730 of FIG. 7 andstages 810 and 815 of FIG. 8. The SPS signals may be non-anomaloussignals or may be anomalous signals, such as produced by a spoofedsignal source. A means for receiving SPS signals (Satellite PositioningSystem signals) may be, e.g., the SPS receiver 217 and the one or moreprocessors 210 with dedicated hardware or implementing executable codeor software instructions in memory 211, such as the locationdetermination module 282 in UE 200.

At block 1204, the UE determines whether the received SPS signals arereliable, e.g., as discussed at blocks 510 and 512 in FIG. 5, FIG. 7,and stage 850 of FIG. 8. A means for determining whether the receivedSPS signals are reliable may be, e.g., the one or more processors 210with dedicated hardware or implementing executable code or softwareinstructions in memory 211, such as the anomaly detection module 284 inUE 200.

At block 1206, the UE determines a location estimate to be transmittedto other UEs, wherein a source of information used to determine thelocation estimate is the SPS signals if the received SPS signals aredetermined to be reliable and the source of information used todetermine the location estimate is non-SPS information if the receivedSPS signals are determined to be not reliable, e.g., as discussed atblocks 512 and 514 in FIG. 5, FIG. 7, and stage 860 of FIG. 8. Thenon-SPS information, for example, may be at least one of a cachedlocation for the UE, sensor information, including information fromradar, sonar, lidar, accelerometers, gyroscopes, magnetometers, etc.,received location information for other UEs, received cellular signals,received LAN signals, such WiFi, signals, or other short range signalssuch as UWB, mmWave, etc., or a combination thereof A means fordetermining a location estimate to be transmitted to other UEs, whereina source of information used to determine the location estimate is theSPS signals if the received SPS signals are determined to be reliableand the source of information used to determine the location estimate isnon-SPS information if the received SPS signals are determined to be notreliable may be, e.g., the one or more processors 210 with dedicatedhardware or implementing executable code or software instructions inmemory 211, such as the location determination module 282, the anomalydetection module 284, and the location information report module 286 inUE 200.

At block 1208, the UE transmits to one or more UEs, a wireless messagethat includes the location estimate for the UE and an indication of thesource of information used to generate the location estimate, e.g., asdiscussed at blocks 512, 514, and 516 of FIG. 5, and stages 860 and 870of FIG. 8, and in FIG. 9. In one implementation, the UE is one of avehicle based UE, a roadside unit, pedestrian held UE, or a smartdevice, e.g., as discussed in FIG. 1 and in FIGS. 8 and 9. In oneimplementation, the wireless message may be one of avehicle-to-everything (V2X) message, a peer-to-peer message, orinfrastructure-based message. For example, the wireless message may beone of a Common Awareness Message (CAM), a Decentralized NotificationMessage (DENM), or a Basic Safety Message (BSM). In one implementation,for example, the indication of the source of information may be providedin an information element in a location information message transmittedto the one or more UEs. In one example, the indication of the source ofinformation may be a variable indicating whether the source ofinformation is the SPS signals or the non-SPS information, e.g., asillustrated in Table 3. In another example, the indication of the sourceof information identifies a type of the source of information, e.g., asillustrated in Table 2. The indication of the source of information, forexample, may be a variable that identifies the type of the source ofinformation, as illustrated in Table 2. The type of the source ofinformation may be identified from an enumerated list of types of thesource of information. For example, the enumerated list of types of thesource of information may include, e.g., one or more of SPS signals,cellular signals, local area network (LAN) signals, sidelink signals,time difference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof. A means for transmitting to one or more UEs, amessage that includes the location estimate for the UE and an indicationof the source of information used to generate the location estimate maybe, e.g., the transceiver 240 shown in FIG. 2, and the one or moreprocessors 210 with dedicated hardware or implementing executable codeor software instructions in memory 211, such as the location informationreport module 286 in UE 200.

In one implementation, the UE may provide an indication whether the SPSsignals are reliable in the message transmitted to the one or more UEs,e.g., as illustrated in stage 870 of FIG. 8 and in FIG. 9. A means forproviding an indication whether the SPS signals are reliable in themessage transmitted to the one or more UEs may be, e.g., the transceiver240 shown in FIG. 2, and the one or more processors 210 with dedicatedhardware or implementing executable code or software instructions inmemory 211, such as the location information report module 286 in UE200.

In one implementation, the UE may further determine a first locationestimate based on the SPS signals, e.g., as discussed at stage 502 inFIG. 5 and stage 850 of FIG. 8, and may determine a second locationestimate based on the non-SPS information, e.g., as discussed at stage516 in FIG. 5 and stage 840 of FIG. 8. The UE may compare the firstlocation estimate to the second location estimate, e.g., as discussed atstages 510 and 512 in FIG. 5 and stage 850 and 860 of FIG. 8. Forexample, whether the received SPS signals are reliable may be determinedbased on the comparison of the first location estimate to the secondlocation estimate, e.g., as discussed at stages 510 and 512 in FIG. 5and stage 850 and 860 of FIG. 8. A means for determining a firstlocation estimate based on the SPS signals may be, e.g., the one or moreprocessors 210 with dedicated hardware or implementing executable codeor software instructions in memory 211, such as the locationdetermination module 282 in UE 200. A means for determining a secondlocation estimate based on the non-SPS information may be, e.g., the oneor more processors 210 with dedicated hardware or implementingexecutable code or software instructions in memory 211, such as thelocation determination module 282 in UE 200. A means for comparing thefirst location estimate to the second location estimate may be, e.g.,the one or more processors 210 with dedicated hardware or implementingexecutable code or software instructions in memory 211, such as theanomaly detection module 284 in UE 200.

For example, in one implementation, the UE may determine the locationestimate to be transmitted to the other UEs by selecting the firstlocation estimate to be transmitted to the other UEs if the received SPSsignals are determined to be reliable and selecting the second locationestimate to be transmitted to the other UEs if the received SPS signalsare determined to be not reliable, e.g., as discussed at stages 510 and512 in FIG. 5 and stage 850 and 860 of FIG. 8. A means for selecting thefirst location estimate to be transmitted to the other UEs if thereceived SPS signals are determined to be reliable and selecting thesecond location estimate to be transmitted to the other UEs if thereceived SPS signals are determined to be not reliable may be, e.g., theone or more processors 210 with dedicated hardware or implementingexecutable code or software instructions in memory 211, such as theanomaly detection module 284, and the location information report module286 in UE 200.

FIG. 13 is a flow chart 1300 illustrating a method of transmittinglocation information by a user equipment (UE), such as UE 200.

At block 1302, the UE receives from a second UE a wireless message thatincludes a location estimate for the second UE and an indication of asource of information used to generate the location estimate, whereinthe source of information comprises SPS (Satellite Positioning System)signals or non-SPS information, e.g., as discussed in block 504 of FIG.5, stage 830 and 870 of FIG. 8, and FIG. 9. In one implementation, theUE is one of a vehicle based UE, a roadside unit, pedestrian held UE, ora smart device, e.g., as discussed in FIG. 1 and in FIGS. 8 and 9. Inone implementation, the wireless message may be one of avehicle-to-everything (V2X) message, a peer-to-peer message, orinfrastructure-based message. For example, the message may be one of aCommon Awareness Message (CAM), a Decentralized Notification Message(DENM), or a Basic Safety Message (BSM). In one implementation, forexample, the indication of the source of information may be provided inan information element in a location information message transmitted tothe one or more UEs. In one example, the indication of the source ofinformation may be a variable indicating whether the source ofinformation is the SPS signals or the non-SPS information, e.g., asillustrated in Table 3. In another example, the indication of the sourceof information identifies a type of the source of information, e.g., asillustrated in Table 2. The indication of the source of information, forexample, may be a variable that identifies the type of the source ofinformation, as illustrated in Table 2. The type of the source ofinformation may be identified from an enumerated list of types of thesource of information. For example, the enumerated list of types of thesource of information may include, e.g., one or more of SPS signals,cellular signals, local area network (LAN) signals, sidelink signals,time difference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

A means for receiving from a second UE a message that includes alocation estimate for the second UE and an indication of a source ofinformation used to generate the location estimate, wherein the sourceof information comprises SPS (Satellite Positioning System) signals ornon-SPS information may be, e.g., the transceiver 240 shown in FIG. 2,and the one or more processors 210 with dedicated hardware orimplementing executable code or software instructions in memory 211,such as the location information report module 286 in UE 200.

At block 1304, the UE determines a location estimate for the first UEbased, at least in part, on the indication of the source of informationused to generate the location estimate received from the second UE,e.g., as discussed in blocks 502, 516, 510, and 514 of FIG. 5, stage840, 850, and 860 of FIG. 8, and FIG. 9. A means for determining alocation estimate for the first UE based, at least in part, on theindication of the source of information used to generate the locationestimate received from the second UE may be, e.g., the transceiver 240shown in FIG. 2, and the one or more processors 210 with dedicatedhardware or implementing executable code or software instructions inmemory 211, such as the location determination module 282 in UE 200.

In one implementation, the UE may determine a location estimate for thefirst UE based, at least in part, on the indication of the source ofinformation by receiving SPS signals, e.g., as discussed in FIG. 5,stages 710 and 730 of FIG. 7 and stages 810 and 815 of FIG. 8, determinewhether the received SPS signals are reliable based at least in part onthe indication of the source of information used to generate thelocation estimate received from the second UE, e.g., as discussed atblocks 510 and 512 in FIG. 5, FIG. 7, and stage 850 of FIG. 8, anddetermine the location estimate for the first UE using the received SPSsignals if the received SPS signals are determined to be reliable andusing non-SPS information if the received SPS signals are determined tobe not reliable, e.g., as discussed at blocks 512 and 514 in FIG. 5,FIG. 7, and stage 860 of FIG. 8. For example, the non-SPS informationmay comprise at least one of a cached location for the UE, sensorinformation, including information from radar, sonar, lidar,accelerometers, gyroscopes, magnetometers, etc., received locationinformation for other UEs, received cellular signals, received LANsignals, such WiFi, signals, or other short range signals such as UWB,mmWave, etc., or a combination thereof. A means for receiving SPSsignals may be, e.g., the SPS receiver 217 and the one or moreprocessors 210 with dedicated hardware or implementing executable codeor software instructions in memory 211, such as the locationdetermination module 282 in UE 200. A means for determining whether thereceived SPS signals are reliable based at least in part on theindication of the source of information used to generate the locationestimate received from the second UE may be, e.g., the one or moreprocessors 210 with dedicated hardware or implementing executable codeor software instructions in memory 211, such as the anomaly detectionmodule 284 in UE 200. A means for determining the location estimate forthe first UE using the received SPS signals if the received SPS signalsare determined to be reliable and using non-SPS information if thereceived SPS signals are determined to be not reliable may be, e.g., theone or more processors 210 with dedicated hardware or implementingexecutable code or software instructions in memory 211, such as thelocation determination module 282, the anomaly detection module 284, andthe location information report module 286 in UE 200.

In one implementation, the UE may receive an indication whether SPSsignals received by the second UE are reliable in the message receivedfrom the second UE, wherein determining the location estimate for thefirst UE is further based, at least in part, on the indication whetherthe SPS signals received by the second UE are reliable, e.g., asillustrated in stage 870 of FIG. 8 and in FIG. 9. A means for receivingan indication whether SPS signals received by the second UE are reliablein the message received from the second UE, wherein determining thelocation estimate for the first UE is further based, at least in part,on the indication whether the SPS signals received by the second UE arereliable may be, e.g., the transceiver 240 shown in FIG. 2, and the oneor more processors 210 with dedicated hardware or implementingexecutable code or software instructions in memory 211, such as thelocation information report module 286 in UE 200.

Reference throughout this specification to “one example”, “an example”,“certain examples”, or “exemplary implementation” means that aparticular feature, structure, or characteristic described in connectionwith the feature and/or example may be included in at least one featureand/or example of claimed subject matter. Thus, the appearances of thephrase “in one example”, “an example”, “in certain examples” or “incertain implementations” or other like phrases in various placesthroughout this specification are not necessarily all referring to thesame feature, example, and/or limitation. Furthermore, the particularfeatures, structures, or characteristics may be combined in one or moreexamples and/or features.

Some portions of the detailed description included herein are presentedin terms of algorithms or symbolic representations of operations onbinary digital signals stored within a memory of a specific apparatus orspecial purpose computing device or platform. In the context of thisparticular specification, the term specific apparatus or the likeincludes a general-purpose computer once it is programmed to performparticular operations pursuant to instructions from program software.Algorithmic descriptions or symbolic representations are examples oftechniques used by those of ordinary skill in the signal processing orrelated arts to convey the substance of their work to others skilled inthe art. An algorithm is here, and generally, is considered to be aself-consistent sequence of operations or similar signal processingleading to a desired result. In this context, operations or processinginvolve physical manipulation of physical quantities. Typically,although not necessarily, such quantities may take the form ofelectrical or magnetic signals capable of being stored, transferred,combined, compared, or otherwise manipulated. It has proven convenientat times, principally for reasons of common usage, to refer to suchsignals as bits, data, values, elements, symbols, characters, terms,numbers, numerals, or the like. It should be understood, however, thatall of these or similar terms are to be associated with appropriatephysical quantities and are merely convenient labels. Unlessspecifically stated otherwise, as apparent from the discussion herein,it is appreciated that throughout this specification discussionsutilizing terms such as “processing,” “computing,” “calculating,”“determining” or the like refer to actions or processes of a specificapparatus, such as a special purpose computer, special purpose computingapparatus or a similar special purpose electronic computing device. Inthe context of this specification, therefore, a special purpose computeror a similar special purpose electronic computing device is capable ofmanipulating or transforming signals, typically represented as physicalelectronic or magnetic quantities within memories, registers, or otherinformation storage devices, transmission devices, or display devices ofthe special purpose computer or similar special purpose electroniccomputing device.

In the preceding detailed description, numerous specific details havebeen set forth to provide a thorough understanding of claimed subjectmatter. However, it will be understood by those skilled in the art thatclaimed subject matter may be practiced without these specific details.In other instances, methods and apparatuses that would be known by oneof ordinary skill have not been described in detail so as not to obscureclaimed subject matter.

The terms, “and”, “or”, and “and/or” as used herein may include avariety of meanings that also are expected to depend at least in partupon the context in which such terms are used. Typically, “or” if usedto associate a list, such as A, B or C, is intended to mean A, B, and C,here used in the inclusive sense, as well as A, B or C, here used in theexclusive sense. In addition, the term “one or more” as used herein maybe used to describe any feature, structure, or characteristic in thesingular or may be used to describe a plurality or some othercombination of features, structures, or characteristics. Though, itshould be noted that this is merely an illustrative example and claimedsubject matter is not limited to this example.

While there has been illustrated and described what are presentlyconsidered to be example features, it will be understood by thoseskilled in the art that various other modifications may be made, andequivalents may be substituted, without departing from claimed subjectmatter. Additionally, many modifications may be made to adapt aparticular situation to the teachings of claimed subject matter withoutdeparting from the central concept described herein.

Implementation examples are described in the following numbered clauses:

Clause 1. A method performed by a user equipment (UE) for transmittinglocation information, the method comprising:

receiving SPS (Satellite Positioning System) signals;

determining whether the received SPS signals are reliable;

determining a location estimate to be transmitted to other UEs, whereina source of information used to determine the location estimate is theSPS signals if the received SPS signals are determined to be reliableand the source of information used to determine the location estimate isnon-SPS information if the received SPS signals are determined to be notreliable; and

transmitting to one or more UEs, a wireless message that includes thelocation estimate for the UE and an indication of the source ofinformation used to generate the location estimate.

Clause 2. The method of clause 1, wherein the indication of the sourceof information is provided in an information element in a locationinformation message transmitted to the one or more UEs.

Clause 3. The method of either of clauses 1 or 2, wherein the indicationof the source of information comprises a variable indicating whether thesource of information is the SPS signals or the non-SPS information.

Clause 4. The method of any of clauses 1-3, wherein the indication ofthe source of information identifies a type of the source ofinformation.

Clause 5. The method of clause 4, wherein the indication of the sourceof information comprises a variable that identifies the type of thesource of information.

Clause 6. The method of clause 4, wherein the type of the source ofinformation is identified from an enumerated list of types of the sourceof information.

Clause 7. The method of clause 6, wherein the enumerated list of typesof the source of information comprises one or more of SPS signals,cellular signals, local area network (LAN) signals, sidelink signals,time difference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

Clause 8. The method of any of clauses 1-7, further comprising providingan indication whether the SPS signals are reliable in the wirelessmessage transmitted to the one or more UEs.

Clause 9. The method of any of clauses 1-8, further comprising:

determining a first location estimate based on the SPS signals;

determining a second location estimate based on the non-SPS information;and

comparing the first location estimate to the second location estimate;

wherein whether the received SPS signals are reliable is determinedbased on the comparison of the first location estimate to the secondlocation estimate.

Clause 10. The method of clause 9, wherein the determining the locationestimate to be transmitted to the other UEs comprises selecting thefirst location estimate to be transmitted to the other UEs if thereceived SPS signals are determined to be reliable and selecting thesecond location estimate to be transmitted to the other UEs if thereceived SPS signals are determined to be not reliable.

Clause 11. The method of any of clauses 1-10, wherein the non-SPSinformation comprises at least one of a cached location for the UE,sensor information, received location information for other UEs,received cellular signals, received local area network (LAN) signals, ora combination thereof.

Clause 12. The method of any of clauses 1-11, wherein the UE is one of avehicle based UE, a roadside unit, pedestrian held UE, or a smartdevice.

Clause 13. The method of any of clauses 1-12, wherein the wirelessmessage is one of a vehicle-to-everything (V2X) message, a peer-to-peermessage, or infrastructure-based message.

Clause 14. The method of any of clauses 1-13, wherein the wirelessmessage is one of a Common Awareness Message (CAM), a DecentralizedNotification Message (DENM), or a Basic Safety Message (BSM).

Clause 15. A user equipment (UE) configured for transmitting locationinformation, the UE comprising:

at least one wireless transceiver configured to wirelessly communicatewith entities in a wireless network;

an SPS (Satellite Positioning System) receiver configured to receive SPSsignals;

at least one memory; and

at least one processor coupled to the at least one wireless transceiver,the SPS receiver, and the at least one memory, wherein the at least oneprocessor is configured to:

receive, via the SPS receiver, SPS signals;

determine whether the received SPS signals are reliable;

determine a location estimate to be transmitted to other UEs, wherein asource of information used to determine the location estimate is the SPSsignals if the received SPS signals are determined to be reliable andthe source of information used to determine the location estimate isnon-SPS information if the received SPS signals are determined to be notreliable; and

transmit, via the at least one wireless transceiver, to one or more UEs,a wireless message that includes the location estimate for the UE and anindication of the source of information used to generate the locationestimate.

Clause 16. The UE of clause 15, wherein the indication of the source ofinformation is provided in an information element in a locationinformation message transmitted to the one or more UEs.

Clause 17. The UE of either of clauses 15 or 16, wherein the indicationof the source of information comprises a variable indicating whether thesource of information is the SPS signals or the non-SPS information.

Clause 18. The UE of any of clauses 15-17, wherein the indication of thesource of information identifies a type of the source of information.

Clause 19. The UE of clause 18, wherein the indication of the source ofinformation comprises a variable that identifies the type of the sourceof information.

Clause 20. The UE of clause 18, wherein the type of the source ofinformation is identified from an enumerated list of types of the sourceof information.

Clause 21. The UE of clause 20, wherein the enumerated list of types ofthe source of information comprises one or more of SPS signals, cellularsignals, local area network (LAN) signals, sidelink signals, timedifference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

Clause 22. The UE of any of clauses 15-21, wherein the at least oneprocessor is further configured to provide an indication whether the SPSsignals are reliable in the wireless message transmitted to the one ormore UEs.

Clause 23. The UE of any of clauses 15-22, wherein the at least oneprocessor is further configured to:

determine a first location estimate based on the SPS signals;

determine a second location estimate based on the non-SPS information;and

compare the first location estimate to the second location estimate;

wherein whether the received SPS signals are reliable is determinedbased on the comparison of the first location estimate to the secondlocation estimate.

Clause 24. The UE of clause 23, wherein the at least one processor isconfigured to determine the location estimate to be transmitted to theother UEs by being configured to select the first location estimate tobe transmitted to the other UEs if the received SPS signals aredetermined to be reliable and to select the second location estimate tobe transmitted to the other UEs if the received SPS signals aredetermined to be not reliable.

Clause 25. The UE of any of clauses 15-24, wherein the non-SPSinformation comprises at least one of a cached location for the UE,sensor information, received location information for other UEs,received cellular signals, received local area network (LAN) signals, ora combination thereof.

Clause 26. The UE of any of clauses 15-25, wherein the UE is one of avehicle based UE, a roadside unit, pedestrian held UE, or a smartdevice.

Clause 27. The UE of any of clauses 15-26, wherein the wireless messageis one of a vehicle-to-everything (V2X) message, a peer-to-peer message,or infrastructure-based message.

Clause 28. The UE of any of clauses 15-27, wherein the wireless messageis one of a Common Awareness Message (CAM), a Decentralized NotificationMessage (DENM), or a Basic Safety Message (BSM).

Clause 29. A user equipment (UE) configured for transmitting locationinformation, the UE comprising:

means for receiving SPS (Satellite Positioning System) signals;

means for determining whether the received SPS signals are reliable;

means for determining a location estimate to be transmitted to otherUEs, wherein a source of information used to determine the locationestimate is the SPS signals if the received SPS signals are determinedto be reliable and the source of information used to determine thelocation estimate is non-SPS information if the received SPS signals aredetermined to be not reliable; and

means for transmitting to one or more UEs, a wireless message thatincludes the location estimate for the UE and an indication of thesource of information used to generate the location estimate.

Clause 30. The UE of clause 29, wherein the indication of the source ofinformation is provided in an information element in a locationinformation wireless message transmitted to the one or more UEs.

Clause 31. The UE of either of clauses 29 or 30, wherein the indicationof the source of information comprises a variable indicating whether thesource of information is the SPS signals or the non-SPS information.

Clause 32. The UE of any of clauses 29-31, wherein the indication of thesource of information identifies a type of the source of information.

Clause 33. The UE of clause 32, wherein the indication of the source ofinformation comprises a variable that identifies the type of the sourceof information.

Clause 34. The UE of clause 32, wherein the type of the source ofinformation is identified from an enumerated list of types of the sourceof information.

Clause 35. The UE of clause 34, wherein the enumerated list of types ofthe source of information comprises one or more of SPS signals, cellularsignals, local area network (LAN) signals, sidelink signals, timedifference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

Clause 36. The UE of any of clauses 29-35, further comprising means forproviding an indication whether the SPS signals are reliable in thewireless message transmitted to the one or more UEs.

Clause 37. The UE of any of clauses 29-35, further comprising:

means for determining a first location estimate based on the SPSsignals;

means for determining a second location estimate based on the non-SPSinformation; and

means for comparing the first location estimate to the second locationestimate;

wherein whether the received SPS signals are reliable is determinedbased on the comparison of the first location estimate to the secondlocation estimate.

Clause 38. The UE of clause 37, wherein the means for determining thelocation estimate to be transmitted to the other UEs comprises means forselecting the first location estimate to be transmitted to the other UEsif the received SPS signals are determined to be reliable and means forselecting the second location estimate to be transmitted to the otherUEs if the received SPS signals are determined to be not reliable.

Clause 39. The UE of any of clauses 29-38, wherein the non-SPSinformation comprises at least one of a cached location for the UE,sensor information, received location information for other UEs,received cellular signals, received local area network (LAN) signals, ora combination thereof.

Clause 40. The UE of any of clauses 29-39, wherein the UE is one of avehicle based UE, a roadside unit, pedestrian held UE, or a smartdevice.

Clause 41. The UE of any of clauses 29-40, wherein the wireless messageis one of a vehicle-to-everything (V2X) message, a peer-to-peer message,or infrastructure-based message.

Clause 42. The UE of any of clauses 29-41, wherein the wireless messageis one of a Common Awareness Message (CAM), a Decentralized NotificationMessage (DENM), or a Basic Safety Message (BSM).

Clause 43. A non-transitory storage medium including program code storedthereon, the program code is operable to configure at least oneprocessor in a user equipment (UE) for transmitting locationinformation, the program code including instructions to:

receive SPS (Satellite Positioning System) signals;

determine whether the received SPS signals are reliable;

determine a location estimate to be transmitted to other UEs, wherein asource of information used to determine the location estimate is the SPSsignals if the received SPS signals are determined to be reliable andthe source of information used to determine the location estimate isnon-SPS information if the received SPS signals are determined to be notreliable; and

transmit to one or more UEs, a wireless message that includes thelocation estimate for the UE and an indication of the source ofinformation used to generate the location estimate.

Clause 44. The non-transitory storage medium of clause 43, wherein theindication of the source of information is provided in an informationelement in a location information message transmitted to the one or moreUEs.

Clause 45. The non-transitory storage medium of either of clauses 43 or44, wherein the indication of the source of information comprises avariable indicating whether the source of information is the SPS signalsor the non-SPS information.

Clause 46. The non-transitory storage medium of any of clauses 43-45,wherein the indication of the source of information identifies a type ofthe source of information.

Clause 47. The non-transitory storage medium of clause 46, wherein theindication of the source of information comprises a variable thatidentifies the type of the source of information.

Clause 48. The non-transitory storage medium of clause 46, wherein thetype of the source of information is identified from an enumerated listof types of the source of information.

Clause 49. The non-transitory storage medium of clause 48, wherein theenumerated list of types of the source of information comprises one ormore of SPS signals, cellular signals, local area network (LAN) signals,sidelink signals, time difference of arrival (TDOA) positioning, angleof arrival (AoA) positioning, and received signal strength (RSS)positioning, or any combinations thereof.

Clause 50. The non-transitory storage medium of any of clauses 43-49,the program code further including instructions to provide an indicationwhether the SPS signals are reliable in the wireless message transmittedto the one or more UEs.

Clause 51. The non-transitory storage medium of any of clauses 43-50,the program code further including instructions to:

determine a first location estimate based on the SPS signals;

determine a second location estimate based on the non-SPS information;and

compare the first location estimate to the second location estimate;

wherein whether the received SPS signals are reliable is determinedbased on the comparison of the first location estimate to the secondlocation estimate.

Clause 52. The non-transitory storage medium of clause 51, wherein theinstructions to determine the location estimate to be transmitted to theother UEs comprises the instructions to select the first locationestimate to be transmitted to the other UEs if the received SPS signalsare determined to be reliable and select the second location estimate tobe transmitted to the other UEs if the received SPS signals aredetermined to be not reliable.

Clause 53. The non-transitory storage medium of any of clauses 43-52,wherein the non-SPS information comprises at least one of a cachedlocation for the UE, sensor information, received location informationfor other UEs, received cellular signals, received local area network(LAN) signals, or a combination thereof.

Clause 54. The non-transitory storage medium of any of clauses 43-53,wherein the UE is one of a vehicle based UE, a roadside unit, pedestrianheld UE, or a smart device.

Clause 55. The non-transitory storage medium of any of clauses 43-54,wherein the wireless message is one of a vehicle-to-everything (V2X)message, a peer-to-peer message, or infrastructure-based message.

Clause 56. The non-transitory storage medium of any of clauses 43-55,wherein the wireless message is one of a Common Awareness Message (CAM),a Decentralized Notification Message (DENM), or a Basic Safety Message(BSM).

Clause 57. A method performed by a first user equipment (UE) fortransmission of location information, the method comprising:

receiving from a second UE a wireless message that includes a locationestimate for the second UE and an indication of a source of informationused to generate the location estimate, wherein the source ofinformation comprises SPS (Satellite Positioning System) signals ornon-SPS information; and

determining a location estimate for the first UE based, at least inpart, on the indication of the source of information used to generatethe location estimate received from the second UE.

Clause 58. The method of clause 57, wherein determining a locationestimate for the first UE based, at least in part, on the indication ofthe source of information comprises:

receiving SPS signals;

determining whether the received SPS signals are reliable based, atleast in part, on the indication of the source of information used togenerate the location estimate received from the second UE; and

determining the location estimate for the first UE using the receivedSPS signals if the received SPS signals are determined to be reliableand using non-SPS information if the received SPS signals are determinedto be not reliable.

Clause 59. The method of clause 58, wherein the non-SPS informationcomprises at least one of a cached location for the UE, sensorinformation, received location information for other UEs, receivedcellular signals, received local area network (LAN) signals, or acombination thereof.

Clause 60. The method of any of clauses 57-59, wherein the indication ofthe source of information is provided in an information element in alocation information message received from the second UE.

Clause 61. The method of any of clauses 57-60, wherein the indication ofthe source of information comprises a variable indicating whether thesource of information is the SPS signals or the non-SPS information.

Clause 62. The method of any of clauses 57-61, wherein the indication ofthe source of information identifies a type of the source ofinformation.

Clause 63. The method of clause 62, wherein the indication of the sourceof information comprises a variable that identifies the type of thesource of information.

Clause 64. The method of clause 62, wherein the type of the source ofinformation is identified from an enumerated list of types of the sourceof information.

Clause 65. The method of clause 64, wherein the enumerated list of typesof the source of information comprises one or more of SPS signals,cellular signals, local area network (LAN) signals, sidelink signals,time difference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

Clause 66. The method of any of clauses 57-65, further comprisingreceiving an indication whether SPS signals received by the second UEare reliable in the wireless message received from the second UE,wherein determining the location estimate for the first UE is furtherbased, at least in part, on the indication whether the SPS signalsreceived by the second UE are reliable.

Clause 67. The method of any of clauses 57-66, wherein the first UE isone of a vehicle based UE, a roadside unit, pedestrian held UE, or asmart device.

Clause 68. The method of any of clauses 57-67, wherein the wirelessmessage is one of a vehicle-to-everything (V2X) message, a peer-to-peermessage, or infrastructure-based message.

Clause 69. The method of any of clauses 57-68, wherein the wirelessmessage is one of a Common Awareness Message (CAM), a DecentralizedNotification Message (DENM), or a Basic Safety Message (BSM).

Clause 70. A first user equipment (UE) configured for transmittinglocation information, the first UE comprising:

at least one wireless transceiver configured to wirelessly communicatewith entities in a wireless network;

an SPS (Satellite Positioning System) receiver configured to receive SPSsignals;

at least one memory; and

at least one processor coupled to the at least one wireless transceiver,the SPS receiver, and the at least one memory, wherein the at least oneprocessor is configured to:

receive, via the at least one wireless transceiver, from a second UE awireless message that includes a location estimate for the second UE andan indication of a source of information used to generate the locationestimate, wherein the source of information comprises SPS signals ornon-SPS information; and

determine a location estimate for the first UE based, at least in part,on the indication of the source of information used to generate thelocation estimate received from the second UE.

Clause 71. The first UE of clause 70, wherein the at least one processoris configured to determine a location estimate for the first UE based,at least in part, on the indication of the source of information bybeing configured to:

receive SPS signals via the SPS receiver;

determine whether the received SPS signals are reliable based, at leastin part, on the indication of the source of information used to generatethe location estimate received from the second UE; and

determine the location estimate for the first UE using the received SPSsignals if the received SPS signals are determined to be reliable andusing non-SPS information if the received SPS signals are determined tobe not reliable.

Clause 72. The first UE of clause 71, wherein the non-SPS informationcomprises at least one of a cached location for the UE, sensorinformation, received location information for other UEs, receivedcellular signals, received local area network (LAN) signals, or acombination thereof.

Clause 73. The first UE of any of clauses 70-72, wherein the indicationof the source of information is provided in an information element in alocation information message received from the second UE.

Clause 74. The first UE of any of clauses 70-73, wherein the indicationof the source of information comprises a variable indicating whether thesource of information is the SPS signals or the non-SPS information.

Clause 75. The first UE of any of clauses 70-74, wherein the indicationof the source of information identifies a type of the source ofinformation.

Clause 76. The first UE of clause 75, wherein the indication of thesource of information comprises a variable that identifies the type ofthe source of information.

Clause 77. The first UE of clause 75, wherein the type of the source ofinformation is identified from an enumerated list of types of the sourceof information.

Clause 78. The first UE of clause 77, wherein the enumerated list oftypes of the source of information comprises one or more of SPS signals,cellular signals, local area network (LAN) signals, sidelink signals,time difference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

Clause 79. The first UE of any of clauses 70-78, wherein the at leastone processor is further configured to receive an indication whether SPSsignals received by the second UE are reliable in the wireless messagereceived from the second UE, wherein the location estimate for the firstUE is determined further based, at least in part, on the indicationwhether the SPS signals received by the second UE are reliable.

Clause 80. The first UE of any of clauses 70-79, wherein the first UE isone of a vehicle based UE, a roadside unit, pedestrian held UE, or asmart device.

Clause 81. The first UE of any of clauses 70-80, wherein the wirelessmessage is one of a vehicle-to-everything (V2X) message, a peer-to-peermessage, or infrastructure-based message.

Clause 82. The first UE of any of clauses 70-81, wherein the wirelessmessage is one of a Common Awareness Message (CAM), a DecentralizedNotification Message (DENM), or a Basic Safety Message (BSM).

Clause 83. A first user equipment (UE) configured for transmittinglocation information, the first UE comprising:

means for receiving from a second UE a wireless message that includes alocation estimate for the second UE and an indication of a source ofinformation used to generate the location estimate, wherein the sourceof information comprises SPS (Satellite Positioning System) signals ornon-SPS information; and

means for determining a location estimate for the first UE based, atleast in part, on the indication of the source of information used togenerate the location estimate received from the second UE.

Clause 84. The first UE of clause 83, wherein the means for determininga location estimate for the first UE based, at least in part, on theindication of the source of information comprises:

means for receiving SPS signals;

means for determining whether the received SPS signals are reliablebased, at least in part, on the indication of the source of informationused to generate the location estimate received from the second UE; and

means for determining the location estimate for the first UE using thereceived SPS signals if the received SPS signals are determined to bereliable and using non-SPS information if the received SPS signals aredetermined to be not reliable.

Clause 85. The first UE of clause 84, wherein the non-SPS informationcomprises at least one of a cached location for the UE, sensorinformation, received location information for other UEs, receivedcellular signals, received local area network (LAN) signals, or acombination thereof.

Clause 86. The first UE of any of clauses 83-85, wherein the indicationof the source of information is provided in an information element in alocation information message received from the second UE.

Clause 87. The first UE of any of clauses 83-86, wherein the indicationof the source of information comprises a variable indicating whether thesource of information is the SPS signals or the non-SPS information.

Clause 88. The first UE of any of clauses 83-87, wherein the indicationof the source of information identifies a type of the source ofinformation.

Clause 89. The first UE of clause 88, wherein the indication of thesource of information comprises a variable that identifies the type ofthe source of information.

Clause 90. The first UE of clause 88, wherein the type of the source ofinformation is identified from an enumerated list of types of the sourceof information.

Clause 91. The first UE of clause 90, wherein the enumerated list oftypes of the source of information comprises one or more of SPS signals,cellular signals, local area network (LAN) signals, sidelink signals,time difference of arrival (TDOA) positioning, angle of arrival (AoA)positioning, and received signal strength (RSS) positioning, or anycombinations thereof.

Clause 92. The first UE of any of clauses 83-91, further comprisingmeans for receiving an indication whether SPS signals received by thesecond UE are reliable in the wireless message received from the secondUE, wherein the location estimate for the first UE is further determinedbased, at least in part, on the indication whether the SPS signalsreceived by the second UE are reliable.

Clause 93. The first UE of any of clauses 83-92, wherein the first UE isone of a vehicle based UE, a roadside unit, pedestrian held UE, or asmart device.

Clause 94. The first UE of any of clauses 83-93, wherein the wirelessmessage is one of a vehicle-to-everything (V2X) message, a peer-to-peermessage, or infrastructure-based message.

Clause 95. The first UE of any of clauses 83-94, wherein the wirelessmessage is one of a Common Awareness Message (CAM), a DecentralizedNotification Message (DENM), or a Basic Safety Message (BSM).

Clause 96. A non-transitory storage medium including program code storedthereon, the program code is operable to configure at least oneprocessor in a first user equipment (UE) configured for transmittinglocation information, the program code including instructions to:

receive from a second UE a wireless message that includes a locationestimate for the second UE and an indication of a source of informationused to generate the location estimate, wherein the source ofinformation comprises SPS (Satellite Positioning System) signals ornon-SPS information; and

determine a location estimate for the first UE based, at least in part,on the indication of the source of information used to generate thelocation estimate received from the second UE.

Clause 97. The non-transitory storage medium of clause 96, wherein theinstructions to determine a location estimate for the first UE based, atleast in part, on the indication of the source of information compriseinstructions to:

receive SPS signals;

determine whether the received SPS signals are reliable based, at leastin part, on the indication of the source of information used to generatethe location estimate received from the second UE; and

determine the location estimate for the first UE using the received SPSsignals if the received SPS signals are determined to be reliable andusing non-SPS information if the received SPS signals are determined tobe not reliable.

Clause 98. The non-transitory storage medium of clause 97, wherein thenon-SPS information comprises at least one of a cached location for theUE, sensor information, received location information for other UEs,received cellular signals, received local area network (LAN) signals, ora combination thereof.

Clause 99. The non-transitory storage medium of any of clauses 96-98,wherein the indication of the source of information is provided in aninformation element in a location information message received from thesecond UE.

Clause 100. The non-transitory storage medium of any of clauses 96-99,wherein the indication of the source of information comprises a variableindicating whether the source of information is the SPS signals or thenon-SPS information.

Clause 101. The non-transitory storage medium of any of clauses 96-100,wherein the indication of the source of information identifies a type ofthe source of information.

Clause 102. The non-transitory storage medium of clause 101, wherein theindication of the source of information comprises a variable thatidentifies the type of the source of information.

Clause 103. The non-transitory storage medium of clause 101, wherein thetype of the source of information is identified from an enumerated listof types of the source of information.

Clause 104. The non-transitory storage medium of clause 103, wherein theenumerated list of types of the source of information comprises one ormore of SPS signals, cellular signals, local area network (LAN) signals,sidelink signals, time difference of arrival (TDOA) positioning, angleof arrival (AoA) positioning, and received signal strength (RSS)positioning, or any combinations thereof.

Clause 105. The non-transitory storage medium of any of clauses 96-104,the program code further including instructions to receive an indicationwhether SPS signals received by the second UE are reliable in thewireless message received from the second UE, wherein the locationestimate for the first UE is determined further based, at least in part,on the indication whether the SPS signals received by the second UE arereliable.

Clause 106. The non-transitory storage medium of any of clauses 96-105,wherein the first UE is one of a vehicle based UE, a roadside unit,pedestrian held UE, or a smart device.

Clause 107. The non-transitory storage medium of any of clauses 96-106,wherein the wireless message is one of a vehicle-to-everything (V2X)message, a peer-to-peer message, or infrastructure-based message.

Clause 108. The non-transitory storage medium of any of clauses 96-107,wherein the wireless message is one of a Common Awareness Message (CAM),a Decentralized Notification Message (DENM), or a Basic Safety Message(BSM).

Therefore, it is intended that claimed subject matter not be limited tothe particular examples disclosed, but that such claimed subject mattermay also include all aspects falling within the scope of appendedclaims, and equivalents thereof.

What is claimed is:
 1. A method performed by a user equipment (UE) for transmitting location information, the method comprising: receiving SPS (Satellite Positioning System) signals; determining whether the received SPS signals are reliable; determining a location estimate to be transmitted to other UEs, wherein a source of information used to determine the location estimate is the SPS signals if the received SPS signals are determined to be reliable and the source of information used to determine the location estimate is non-SPS information if the received SPS signals are determined to be not reliable; and transmitting to one or more UEs, a wireless message that includes the location estimate for the UE and an indication of the source of information used to generate the location estimate.
 2. The method of claim 1, wherein the indication of the source of information is provided in an information element in a location information message transmitted to the one or more UEs.
 3. The method of claim 1, wherein the indication of the source of information comprises a variable indicating whether the source of information is the SPS signals or the non-SPS information.
 4. The method of claim 1, wherein the indication of the source of information identifies a type of the source of information.
 5. The method of claim 4, wherein the indication of the source of information comprises a variable that identifies the type of the source of information.
 6. The method of claim 4, wherein the type of the source of information is identified from an enumerated list of types of the source of information, wherein the enumerated list of types of the source of information comprises one or more of SPS signals, cellular signals, local area network (LAN) signals, sidelink signals, time difference of arrival (TDOA) positioning, angle of arrival (AoA) positioning, received signal strength (RSS) positioning, or any combinations thereof.
 7. The method of claim 1, further comprising providing an indication whether the SPS signals are reliable in the wireless message transmitted to the one or more UEs.
 8. The method of claim 1, further comprising: determining a first location estimate based on the SPS signals; determining a second location estimate based on the non-SPS information; and comparing the first location estimate to the second location estimate; wherein whether the received SPS signals are reliable is determined based on the comparison of the first location estimate to the second location estimate.
 9. The method of claim 8, wherein the determining the location estimate to be transmitted to the other UEs comprises selecting the first location estimate to be transmitted to the other UEs if the received SPS signals are determined to be reliable and selecting the second location estimate to be transmitted to the other UEs if the received SPS signals are determined to be not reliable.
 10. The method of claim 1, wherein the non-SPS information comprises at least one of a cached location for the UE, sensor information, received location information for other UEs, received cellular signals, received local area network (LAN) signals, or a combination thereof.
 11. The method of claim 1, wherein the UE is one of a vehicle based UE, a roadside unit, pedestrian held UE, or a smart device.
 12. The method of claim 1, wherein the wireless message is one of a vehicle-to-everything (V2X) message, a peer-to-peer message, infrastructure-based message a Common Awareness Message (CAM), a Decentralized Notification Message (DENM), or a Basic Safety Message (BSM).
 13. A user equipment (UE) configured for transmitting location information, the UE comprising: at least one wireless transceiver configured to wirelessly communicate with entities in a wireless network; an SPS (Satellite Positioning System) receiver configured to receive SPS signals; at least one memory; and at least one processor coupled to the at least one wireless transceiver, the SPS receiver, and the at least one memory, wherein the at least one processor is configured to: receive, via the SPS receiver, SPS signals; determine whether the received SPS signals are reliable; determine a location estimate to be transmitted to other UEs, wherein a source of information used to determine the location estimate is the SPS signals if the received SPS signals are determined to be reliable and the source of information used to determine the location estimate is non-SPS information if the received SPS signals are determined to be not reliable; and transmit, via the at least one wireless transceiver, to one or more UEs, a wireless message that includes the location estimate for the UE and an indication of the source of information used to generate the location estimate.
 14. The UE of claim 13, wherein the indication of the source of information is provided in an information element in a location information message transmitted to the one or more UEs.
 15. The UE of claim 13, wherein the indication of the source of information comprises a variable indicating whether the source of information is the SPS signals or the non-SPS information.
 16. The UE of claim 13, wherein the indication of the source of information identifies a type of the source of information.
 17. The UE of claim 16, wherein the indication of the source of information comprises a variable that identifies the type of the source of information.
 18. The UE of claim 16, wherein the type of the source of information is identified from an enumerated list of types of the source of information, wherein the enumerated list of types of the source of information comprises one or more of SPS signals, cellular signals, local area network (LAN) signals, sidelink signals, time difference of arrival (TDOA) positioning, angle of arrival (AoA) positioning, received signal strength (RSS) positioning, or any combinations thereof.
 19. The UE of claim 13, wherein the at least one processor is further configured to provide an indication whether the SPS signals are reliable in the wireless message transmitted to the one or more UEs.
 20. The UE of claim 13, wherein the at least one processor is further configured to: determine a first location estimate based on the SPS signals; determine a second location estimate based on the non-SPS information; and compare the first location estimate to the second location estimate; wherein whether the received SPS signals are reliable is determined based on the comparison of the first location estimate to the second location estimate.
 21. The UE of claim 20, wherein the at least one processor is configured to determine the location estimate to be transmitted to the other UEs by being configured to select the first location estimate to be transmitted to the other UEs if the received SPS signals are determined to be reliable and to select the second location estimate to be transmitted to the other UEs if the received SPS signals are determined to be not reliable.
 22. The UE of claim 13, wherein the non-SPS information comprises at least one of a cached location for the UE, sensor information, received location information for other UEs, received cellular signals, received local area network (LAN) signals, or a combination thereof.
 23. The UE of claim 13, wherein the UE is one of a vehicle based UE, a roadside unit, pedestrian held UE, or a smart device.
 24. The UE of claim 13, wherein the wireless message is one of a vehicle-to-everything (V2X) message, a peer-to-peer message, infrastructure-based message, a Common Awareness Message (CAM), a Decentralized Notification Message (DENM), or a Basic Safety Message (BSM).
 25. A user equipment (UE) configured for transmitting location information, the UE comprising: means for receiving SPS (Satellite Positioning System) signals; means for determining whether the received SPS signals are reliable; means for determining a location estimate to be transmitted to other UEs, wherein a source of information used to determine the location estimate is the SPS signals if the received SPS signals are determined to be reliable and the source of information used to determine the location estimate is non-SPS information if the received SPS signals are determined to be not reliable; and means for transmitting to one or more UEs, a wireless message that includes the location estimate for the UE and an indication of the source of information used to generate the location estimate.
 26. The UE of claim 25, wherein the indication of the source of information is provided in an information element in a location information wireless message transmitted to the one or more UEs.
 27. The UE of claim 25, wherein the indication of the source of information comprises a variable indicating whether the source of information is the SPS signals or the non-SPS information.
 28. The UE of claim 25, wherein the indication of the source of information identifies a type of the source of information.
 29. The UE of claim 25, further comprising: means for determining a first location estimate based on the SPS signals; means for determining a second location estimate based on the non-SPS information; and means for comparing the first location estimate to the second location estimate; wherein whether the received SPS signals are reliable is determined based on the comparison of the first location estimate to the second location estimate.
 30. A method performed by a first user equipment (UE) for transmission of location information, the method comprising: receiving from a second UE a wireless message that includes a location estimate for the second UE and an indication of a source of information used to generate the location estimate, wherein the source of information comprises SPS (Satellite Positioning System) signals or non-SPS information; and determining a location estimate for the first UE based, at least in part, on the indication of the source of information used to generate the location estimate received from the second UE.
 31. The method of claim 30, wherein determining a location estimate for the first UE at least partially based on the indication of the source of information comprises: receiving SPS signals; determining whether the received SPS signals are reliable based at least partially on the indication of the source of information used to generate the location estimate received from the second UE; and determining the location estimate for the first UE using the received SPS signals if the received SPS signals are determined to be reliable and using non-SPS information if the received SPS signals are determined to be not reliable.
 32. The method of claim 31, wherein the non-SPS information comprises at least one of a cached location for the UE, sensor information, received location information for other UEs, received cellular signals, received local area network (LAN) signals, or a combination thereof.
 33. The method of claim 30, wherein the indication of the source of information is provided in an information element in a location information message received from the second UE.
 34. The method of claim 30, wherein the indication of the source of information comprises a variable indicating whether the source of information is the SPS signals or the non-SPS information.
 35. The method of claim 30, wherein the indication of the source of information identifies a type of the source of information.
 36. The method of claim 35, wherein the indication of the source of information comprises a variable that identifies the type of the source of information.
 37. The method of claim 35, wherein the type of the source of information is identified from an enumerated list of types of the source of information, wherein the enumerated list of types of the source of information comprises one or more of SPS signals, cellular signals, local area network (LAN) signals, sidelink signals, time difference of arrival (TDOA) positioning, angle of arrival (AoA) positioning, received signal strength (RSS) positioning, or any combinations thereof.
 38. The method of claim 30, further comprising receiving an indication whether SPS signals received by the second UE are reliable in the wireless message received from the second UE, wherein determining the location estimate for the first UE is further at least partially based on the indication whether the SPS signals received by the second UE are reliable.
 39. The method of claim 30, wherein the first UE is one of a vehicle based UE, a roadside unit, pedestrian held UE, or a smart device.
 40. The method of claim 30, wherein the wireless message is one of a vehicle-to-everything (V2X) message, a peer-to-peer message, infrastructure-based message, a Common Awareness Message (CAM), a Decentralized Notification Message (DENM), or a Basic Safety Message (BSM).
 41. A first user equipment (UE) configured for transmitting location information, the first UE comprising: at least one wireless transceiver configured to wirelessly communicate with entities in a wireless network; an SPS (Satellite Positioning System) receiver configured to receive SPS signals; at least one memory; and at least one processor coupled to the at least one wireless transceiver, the SPS receiver, and the at least one memory, wherein the at least one processor is configured to: receive, via the at least one wireless transceiver, from a second UE a wireless message that includes a location estimate for the second UE and an indication of a source of information used to generate the location estimate, wherein the source of information comprises SPS signals or non-SPS information; and determine a location estimate for the first UE at least partially based on the indication of the source of information used to generate the location estimate received from the second UE.
 42. The first UE of claim 41, wherein the at least one processor is configured to determine a location estimate for the first UE at least partially based on the indication of the source of information by being configured to: receive SPS signals via the SPS receiver; determine whether the received SPS signals are reliable based at least partially on the indication of the source of information used to generate the location estimate received from the second UE; and determine the location estimate for the first UE using the received SPS signals if the received SPS signals are determined to be reliable and using non-SPS information if the received SPS signals are determined to be not reliable.
 43. The first UE of claim 42, wherein the non-SPS information comprises at least one of a cached location for the UE, sensor information, received location information for other UEs, received cellular signals, received local area network (LAN) signals, or a combination thereof.
 44. The first UE of claim 41, wherein the indication of the source of information is provided in an information element in a location information message received from the second UE.
 45. The first UE of claim 41, wherein the indication of the source of information comprises a variable indicating whether the source of information is the SPS signals or the non-SPS information.
 46. The first UE of claim 41, wherein the indication of the source of information identifies a type of the source of information.
 47. The first UE of claim 46, wherein the indication of the source of information comprises a variable that identifies the type of the source of information.
 48. The first UE of claim 46, wherein the type of the source of information is identified from an enumerated list of types of the source of information, wherein the enumerated list of types of the source of information comprises one or more of SPS signals, cellular signals, local area network (LAN) signals, sidelink signals, time difference of arrival (TDOA) positioning, angle of arrival (AoA) positioning, received signal strength (RSS) positioning, or any combinations thereof.
 49. The first UE of claim 41, wherein the at least one processor is further configured to receive an indication whether SPS signals received by the second UE are reliable in the wireless message received from the second UE, wherein the location estimate for the first UE is determined further at least partially based on the indication whether the SPS signals received by the second UE are reliable.
 50. The first UE of claim 41, wherein the first UE is one of a vehicle based UE, a roadside unit, pedestrian held UE, or a smart device.
 51. The first UE of claim 41, wherein the wireless message is one of a vehicle-to-everything (V2X) message, a peer-to-peer message, infrastructure-based message, a Common Awareness Message (CAM), a Decentralized Notification Message (DENM), or a Basic Safety Message (BSM).
 52. A first user equipment (UE) configured for transmitting location information, the first UE comprising: means for receiving from a second UE a wireless message that includes a location estimate for the second UE and an indication of a source of information used to generate the location estimate, wherein the source of information comprises SPS (Satellite Positioning System) signals or non-SPS information; and means for determining a location estimate for the first UE at least partially based on the indication of the source of information used to generate the location estimate received from the second UE.
 53. The first UE of claim 52, wherein the means for determining a location estimate for the first UE at least partially based on the indication of the source of information comprises: means for receiving SPS signals; means for determining whether the received SPS signals are reliable based at least partially on the indication of the source of information used to generate the location estimate received from the second UE; and means for determining the location estimate for the first UE using the received SPS signals if the received SPS signals are determined to be reliable and using non-SPS information if the received SPS signals are determined to be not reliable.
 54. The first UE of claim 52, wherein the indication of the source of information is provided in an information element in a location information message received from the second UE.
 55. The first UE of claim 52, wherein the indication of the source of information comprises a variable indicating whether the source of information is the SPS signals or the non-SPS information.
 56. The first UE of claim 52, wherein the indication of the source of information identifies a type of the source of information. 